diff --git a/include/fakeit/Mock.hpp b/include/fakeit/Mock.hpp
index fffde197..4cae42e3 100644
--- a/include/fakeit/Mock.hpp
+++ b/include/fakeit/Mock.hpp
@@ -71,7 +71,7 @@ namespace fakeit {
         }
 
         // const
-        template<int id, typename R, typename T, typename ... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename ... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R (T::*vMethod)(arglist...) const) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R> (T::*)(arglist...)>(vMethod);
@@ -79,7 +79,7 @@ namespace fakeit {
         }
 
         // volatile
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...) volatile) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
@@ -87,7 +87,7 @@ namespace fakeit {
         }
 
         // const volatile
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...) const volatile) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
@@ -95,7 +95,7 @@ namespace fakeit {
         }
 
         // no qualifier
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...)) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
@@ -103,7 +103,7 @@ namespace fakeit {
         }
 
         // ref
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...) &) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
@@ -111,7 +111,7 @@ namespace fakeit {
         }
 
         // const ref
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...) const&) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
@@ -119,7 +119,7 @@ namespace fakeit {
         }
 
         // rval ref
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...) &&) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
@@ -127,7 +127,7 @@ namespace fakeit {
         }
 
         // const rval ref
-        template<int id, typename R, typename T, typename... arglist, class = typename std::enable_if<
+        template<size_t id, typename R, typename T, typename... arglist, class = typename std::enable_if<
                 std::is_base_of<T, C>::value>::type>
         MockingContext<internal::WithCommonVoid_t<R>, arglist...> stub(R(T::*vMethod)(arglist...) const&&) {
             auto methodWithoutConstVolatile = reinterpret_cast<internal::WithCommonVoid_t<R>(T::*)(arglist...)>(vMethod);
diff --git a/include/fakeit/MockImpl.hpp b/include/fakeit/MockImpl.hpp
index 96eaa12f..891c337f 100644
--- a/include/fakeit/MockImpl.hpp
+++ b/include/fakeit/MockImpl.hpp
@@ -101,7 +101,7 @@ namespace fakeit {
             return DataMemberStubbingRoot<T, DataType>();
         }
 
-        template<int id, typename R, typename T, typename ... arglist, class = typename std::enable_if<std::is_base_of<T, C>::value>::type>
+        template<size_t id, typename R, typename T, typename ... arglist, class = typename std::enable_if<std::is_base_of<T, C>::value>::type>
         MockingContext<R, arglist...> stubMethod(R(T::*vMethod)(arglist...)) {
             return MockingContext<R, arglist...>(new UniqueMethodMockingContextImpl < id, R, arglist... >
                    (*this, vMethod));
@@ -226,7 +226,7 @@ namespace fakeit {
         };
 
 
-        template<int id, typename R, typename ... arglist>
+        template<size_t id, typename R, typename ... arglist>
         class UniqueMethodMockingContextImpl : public MethodMockingContextImpl<R, arglist...> {
         protected:
 
@@ -323,7 +323,7 @@ namespace fakeit {
             return origMethodPtr;
         }
 
-        template<unsigned int id, typename R, typename ... arglist>
+        template<size_t id, typename R, typename ... arglist>
         RecordedMethodBody<R, arglist...> &stubMethodIfNotStubbed(DynamicProxy<C, baseclasses...> &proxy,
                                                                   R (C::*vMethod)(arglist...)) {
             if (!proxy.isMethodStubbed(vMethod)) {
diff --git a/include/fakeit/api_macros.hpp b/include/fakeit/api_macros.hpp
index 4f099a98..ae89b756 100644
--- a/include/fakeit/api_macros.hpp
+++ b/include/fakeit/api_macros.hpp
@@ -1,9 +1,19 @@
 #pragma once
 
+#include "mockutils/constexpr_hash.hpp"
+
 #ifdef _MSC_VER
 #define __func__ __FUNCTION__
 #endif
 
+#define COUNTER_STRINGIFY( counter ) #counter
+
+#define STUB_ID_STR( counter ) \
+    __FILE__ COUNTER_STRINGIFY(counter)
+
+#define STUB_ID(counter) \
+    fakeit::constExprHash(STUB_ID_STR(counter))
+
 #define MOCK_TYPE(mock) \
     std::remove_reference<decltype((mock).get())>::type
 
@@ -29,13 +39,13 @@
     (mock).dtor().setMethodDetails(#mock,"destructor")
 
 #define Method(mock, method) \
-    (mock).template stub<__COUNTER__>(&MOCK_TYPE(mock)::method).setMethodDetails(#mock,#method)
+    (mock).template stub<STUB_ID(__COUNTER__)>(&MOCK_TYPE(mock)::method).setMethodDetails(#mock,#method)
 
 #define OverloadedMethod(mock, method, prototype) \
-    (mock).template stub<__COUNTER__>(OVERLOADED_METHOD_PTR( mock , method, prototype )).setMethodDetails(#mock,#method)
+    (mock).template stub<STUB_ID(__COUNTER__)>(OVERLOADED_METHOD_PTR( mock , method, prototype )).setMethodDetails(#mock,#method)
 
 #define ConstOverloadedMethod(mock, method, prototype) \
-    (mock).template stub<__COUNTER__>(CONST_OVERLOADED_METHOD_PTR( mock , method, prototype )).setMethodDetails(#mock,#method)
+    (mock).template stub<STUB_ID(__COUNTER__)>(CONST_OVERLOADED_METHOD_PTR( mock , method, prototype )).setMethodDetails(#mock,#method)
 
 #define RefOverloadedMethod(mock, method, prototype) \
     (mock).template stub<__COUNTER__>(REF_OVERLOADED_METHOD_PTR( mock , method, prototype )).setMethodDetails(#mock,#method)
diff --git a/include/mockutils/DynamicProxy.hpp b/include/mockutils/DynamicProxy.hpp
index 2d562f23..e1dcde6c 100644
--- a/include/mockutils/DynamicProxy.hpp
+++ b/include/mockutils/DynamicProxy.hpp
@@ -28,9 +28,9 @@ namespace fakeit {
 
     class InvocationHandlers : public InvocationHandlerCollection {
         std::vector<std::shared_ptr<Destructible>> &_methodMocks;
-        std::vector<unsigned int> &_offsets;
+        std::vector<size_t> &_offsets;
 
-        unsigned int getOffset(unsigned int id) const
+        unsigned int getOffset(size_t id) const
         {
             unsigned int offset = 0;
             for (; offset < _offsets.size(); offset++) {
@@ -42,11 +42,11 @@ namespace fakeit {
         }
 
     public:
-        InvocationHandlers(std::vector<std::shared_ptr<Destructible>> &methodMocks, std::vector<unsigned int> &offsets)
+        InvocationHandlers(std::vector<std::shared_ptr<Destructible>> &methodMocks, std::vector<size_t> &offsets)
                 : _methodMocks(methodMocks), _offsets(offsets) {
         }
 
-        Destructible *getInvocatoinHandlerPtrById(unsigned int id) override {
+        Destructible *getInvocatoinHandlerPtrById(size_t id) override {
             unsigned int offset = getOffset(id);
             std::shared_ptr<Destructible> ptr = _methodMocks[offset];
             return ptr.get();
@@ -108,7 +108,7 @@ namespace fakeit {
         {
         }
 
-        template<int id, typename R, typename ... arglist>
+        template<size_t id, typename R, typename ... arglist>
         void stubMethod(R(C::*vMethod)(arglist...), MethodInvocationHandler<R, arglist...> *methodInvocationHandler) {
             auto offset = VTUtils::getOffset(vMethod);
             MethodProxyCreator<R, arglist...> creator;
@@ -217,7 +217,7 @@ namespace fakeit {
         //
         std::vector<std::shared_ptr<Destructible>> _methodMocks;
         std::vector<std::shared_ptr<Destructible>> _members;
-        std::vector<unsigned int> _offsets;
+        std::vector<size_t> _offsets;
         InvocationHandlers _invocationHandlers;
 
         FakeObject<C, baseclasses...> &getFake() {
diff --git a/include/mockutils/MethodProxy.hpp b/include/mockutils/MethodProxy.hpp
index b9945c65..66ee39d6 100644
--- a/include/mockutils/MethodProxy.hpp
+++ b/include/mockutils/MethodProxy.hpp
@@ -6,7 +6,7 @@ namespace fakeit {
 
     struct MethodProxy {
 
-        MethodProxy(unsigned int id, unsigned int offset, void *vMethod) :
+        MethodProxy(size_t id, unsigned int offset, void *vMethod) :
                 _id(id),
                 _offset(offset),
                 _vMethod(vMethod) {
@@ -16,7 +16,7 @@ namespace fakeit {
             return _offset;
         }
 
-        unsigned int getId() const {
+        size_t getId() const {
             return _id;
         }
 
@@ -25,7 +25,7 @@ namespace fakeit {
         }
 
     private:
-        unsigned int _id;
+        size_t _id;
         unsigned int _offset;
         void *_vMethod;
     };
diff --git a/include/mockutils/MethodProxyCreator.hpp b/include/mockutils/MethodProxyCreator.hpp
index 3d80b21f..23f64953 100644
--- a/include/mockutils/MethodProxyCreator.hpp
+++ b/include/mockutils/MethodProxyCreator.hpp
@@ -11,7 +11,7 @@ namespace fakeit {
     struct InvocationHandlerCollection {
         static const unsigned int VtCookieIndex = 0;
 
-        virtual Destructible *getInvocatoinHandlerPtrById(unsigned int index) = 0;
+        virtual Destructible *getInvocatoinHandlerPtrById(size_t index) = 0;
 
         static InvocationHandlerCollection *getInvocationHandlerCollection(void *instance) {
             VirtualTableBase &vt = VirtualTableBase::getVTable(instance);
@@ -29,7 +29,7 @@ namespace fakeit {
 
     public:
 
-        template<unsigned int id>
+        template<size_t id>
         MethodProxy createMethodProxy(unsigned int offset) {
             return MethodProxy(id, offset, union_cast<void *>(&MethodProxyCreator::methodProxyX < id > ));
         }
@@ -41,7 +41,7 @@ namespace fakeit {
 
     protected:
 
-        R methodProxy(unsigned int id, const typename fakeit::production_arg<arglist>::type... args) {
+        R methodProxy(size_t id, const typename fakeit::production_arg<arglist>::type... args) {
             InvocationHandlerCollection *invocationHandlerCollection = InvocationHandlerCollection::getInvocationHandlerCollection(
                     this);
             MethodInvocationHandler<R, arglist...> *invocationHandler =
@@ -50,7 +50,7 @@ namespace fakeit {
             return invocationHandler->handleMethodInvocation(std::forward<const typename fakeit::production_arg<arglist>::type>(args)...);
         }
 
-        template<int id>
+        template<size_t id>
         R methodProxyX(arglist ... args) {
             return methodProxy(id, std::forward<const typename fakeit::production_arg<arglist>::type>(args)...);
         }
diff --git a/include/mockutils/VTUtils.hpp b/include/mockutils/VTUtils.hpp
index 3256b711..cc0268e1 100644
--- a/include/mockutils/VTUtils.hpp
+++ b/include/mockutils/VTUtils.hpp
@@ -65,7 +65,7 @@ namespace fakeit {
 		}
 
         template<typename C>
-        static unsigned int getVTSize() {
+        static size_t getVTSize() {
             struct Derrived : public C {
                 virtual void endOfVt() {
                 }
diff --git a/include/mockutils/constexpr_hash.hpp b/include/mockutils/constexpr_hash.hpp
new file mode 100644
index 00000000..0a3822c6
--- /dev/null
+++ b/include/mockutils/constexpr_hash.hpp
@@ -0,0 +1,17 @@
+#pragma once
+
+namespace fakeit {
+
+    constexpr size_t _FNV_prime = sizeof(size_t) == 4 ? 16777619ULL : 1099511628211ULL;
+    constexpr size_t _FNV_offset_basis = sizeof(size_t) == 4 ? 2166136261ULL : 14695981039346656037ULL;
+
+    constexpr size_t _constExprHashImpl(const char* str, size_t count) { 
+        return count ? (_constExprHashImpl(str, count - 1) ^ str[count - 1]) * _FNV_prime : _FNV_offset_basis;
+    }
+    
+    template<size_t N>
+    constexpr size_t constExprHash(const char(&str)[N]) {
+        return _constExprHashImpl(str, N);
+    }
+
+}
\ No newline at end of file
diff --git a/include/mockutils/mscpp/VirtualTable.hpp b/include/mockutils/mscpp/VirtualTable.hpp
index 0d57d241..449f6577 100644
--- a/include/mockutils/mscpp/VirtualTable.hpp
+++ b/include/mockutils/mscpp/VirtualTable.hpp
@@ -178,7 +178,7 @@ namespace fakeit {
         }
 
         void copyFrom(VirtualTable<C, baseclasses...> &from) {
-            unsigned int size = VTUtils::getVTSize<C>();
+            auto size = VTUtils::getVTSize<C>();
             for (unsigned int i = 0; i < size; i++) {
                 _firstMethod[i] = from.getMethod(i);
             }
@@ -234,7 +234,7 @@ namespace fakeit {
             setCookie(dtorCookieIndex, method);
         }
 
-        unsigned int getSize() {
+        size_t getSize() {
             return VTUtils::getVTSize<C>();
         }
 
@@ -256,7 +256,7 @@ namespace fakeit {
         static const unsigned int dtorCookieIndex = numOfCookies - 1; // use the last cookie
 
         static void **buildVTArray() {
-            int vtSize = VTUtils::getVTSize<C>();
+            auto vtSize = VTUtils::getVTSize<C>();
             auto array = new void *[vtSize + numOfCookies + 1]{};
             RTTICompleteObjectLocator<C, baseclasses...> *objectLocator = new RTTICompleteObjectLocator<C, baseclasses...>(
                     typeid(C));
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 02af1c4b..ae861015 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -15,6 +15,8 @@ add_executable(FakeIt_tests
     moving_mocks_around.cpp
     msc_stubbing_multiple_values_tests.cpp
     msc_type_info_tests.cpp
+    multiple_translation_units_stub.cpp
+    multiple_translation_units_stub_test.cpp
     overloadded_methods_tests.cpp
     referece_types_tests.cpp
     remove_const_volatile_tests.cpp
diff --git a/tests/multiple_translation_units_stub.cpp b/tests/multiple_translation_units_stub.cpp
new file mode 100644
index 00000000..6f2dc0bb
--- /dev/null
+++ b/tests/multiple_translation_units_stub.cpp
@@ -0,0 +1,12 @@
+#include "multiple_translation_units_stub.h"
+
+
+void stubFunc2(fakeit::Mock<SomeInterface>& mock)
+{
+	fakeit::When(Method(mock, func2)).AlwaysReturn<std::string>("String");
+}
+
+void stubFunc(fakeit::Mock<SomeInterface>& mock)
+{
+	fakeit::When(Method(mock, func)).AlwaysReturn<int>(3);
+}
diff --git a/tests/multiple_translation_units_stub.h b/tests/multiple_translation_units_stub.h
new file mode 100644
index 00000000..084cf17b
--- /dev/null
+++ b/tests/multiple_translation_units_stub.h
@@ -0,0 +1,13 @@
+#pragma once
+
+#include <string>
+
+#include "fakeit.hpp"
+
+struct SomeInterface {
+	virtual int func() = 0;
+	virtual std::string func2() = 0;
+};
+
+void stubFunc2(fakeit::Mock<SomeInterface>& mock);
+void stubFunc(fakeit::Mock<SomeInterface>& mock);
diff --git a/tests/multiple_translation_units_stub_test.cpp b/tests/multiple_translation_units_stub_test.cpp
new file mode 100644
index 00000000..75cf43f4
--- /dev/null
+++ b/tests/multiple_translation_units_stub_test.cpp
@@ -0,0 +1,24 @@
+#include "tpunit++.hpp"
+#include "fakeit.hpp"
+#include "multiple_translation_units_stub.h"
+
+using namespace fakeit;
+
+struct MultipleTranslationUnitsStub : tpunit::TestFixture {
+	MultipleTranslationUnitsStub()
+		: tpunit::TestFixture(
+			TEST(MultipleTranslationUnitsStub::NoCollidingIds)
+			)
+	{}
+
+	void NoCollidingIds() {
+		Mock<SomeInterface> mock;
+		SomeInterface &i = mock.get();
+		
+		stubFunc2(mock);
+		When(Method(mock, func)).Return<int>(1);
+
+		mock.get().func2(); // Uncatchable write access violation if ids collide
+	}
+
+} __MultipleTranslationUnitsStub;