diff --git a/booleanfield.go b/booleanfield.go
index 4bceb9a..841fdbd 100644
--- a/booleanfield.go
+++ b/booleanfield.go
@@ -3,6 +3,7 @@ package gforms
 import (
 	"bytes"
 	"reflect"
+	"strconv"
 )
 
 // It maps value to FormInstance.CleanedData as type `bool`.
@@ -65,6 +66,18 @@ func (f *BooleanFieldInstance) Clean(data Data) error {
 	return nil
 }
 
+func (f *BooleanFieldInstance) SetInitial(v string) {
+	f.V.RawStr = v
+	f.V.RawValue = []string{v}
+	f.V.IsNil = false
+	b, err := strconv.ParseBool(v)
+	if err != nil {
+		f.V.IsNil = true
+	} else {
+		f.V.Value = b
+	}
+}
+
 func (f *BooleanFieldInstance) html() string {
 	var buffer bytes.Buffer
 	cx := new(booleanContext)
diff --git a/booleanfield_test.go b/booleanfield_test.go
index 8ec4dfe..b3a8bf7 100644
--- a/booleanfield_test.go
+++ b/booleanfield_test.go
@@ -66,3 +66,43 @@ func TestFalseBooleanField(t *testing.T) {
 		t.Error("validation error.")
 	}
 }
+
+func TestBooleanFieldDefaultRender(t *testing.T) {
+	Form := DefineForm(NewFields(
+		NewBooleanField("check", nil),
+	))
+	form := Form()
+	html := strings.TrimSpace(form.Html())
+	if html != `<input type="checkbox" name="check">` {
+		t.Errorf(`Incorrect HTML rendered for default boolean field: %s`, html)
+		return
+	}
+}
+
+func TestBooleanFieldInitialFalseRender(t *testing.T) {
+	Form := DefineForm(NewFields(
+		NewBooleanField("check", nil),
+	))
+	form := Form()
+	field, _ := form.GetField("check")
+	field.SetInitial("false")
+	html := strings.TrimSpace(form.Html())
+	if html != `<input type="checkbox" name="check">` {
+		t.Errorf(`Incorrect HTML rendered for SetInitial("false") boolean field: %s`, html)
+		return
+	}
+}
+
+func TestBooleanFieldInitialTrueRender(t *testing.T) {
+	Form := DefineForm(NewFields(
+		NewBooleanField("check", nil),
+	))
+	form := Form()
+	field, _ := form.GetField("check")
+	field.SetInitial("true")
+	html := strings.TrimSpace(form.Html())
+	if html != `<input type="checkbox" name="check" checked>` {
+		t.Errorf(`Incorrect HTML rendered for SetInitial("true") boolean field: %s`, html)
+		return
+	}
+}
\ No newline at end of file
diff --git a/nullbooleanfield.go b/nullbooleanfield.go
index 240462d..59f377b 100644
--- a/nullbooleanfield.go
+++ b/nullbooleanfield.go
@@ -3,6 +3,7 @@ package gforms
 import (
 	"bytes"
 	"reflect"
+	"strconv"
 )
 
 // It maps value to FormInstance.CleanedData as type `bool`.
@@ -63,6 +64,18 @@ func (f *NullBooleanFieldInstance) Clean(data Data) error {
 	return nil
 }
 
+func (f *NullBooleanFieldInstance) SetInitial(v string) {
+	f.V.RawStr = v
+	f.V.RawValue = []string{v}
+	f.V.IsNil = false
+	b, err := strconv.ParseBool(v)
+	if err != nil {
+		f.V.IsNil = true
+	} else {
+		f.V.Value = b
+	}
+}
+
 func (f *NullBooleanFieldInstance) html() string {
 	var buffer bytes.Buffer
 	cx := new(nullBooleanContext)
diff --git a/nullbooleanfield_test.go b/nullbooleanfield_test.go
index 1a90d37..ab51f89 100644
--- a/nullbooleanfield_test.go
+++ b/nullbooleanfield_test.go
@@ -94,3 +94,43 @@ func TestTrueNullBooleanFieldJsonRequired(t *testing.T) {
 		t.Error("Null boolean field should be required.")
 	}
 }
+
+func TestNullBooleanFieldDefaultRender(t *testing.T) {
+	Form := DefineForm(NewFields(
+		NewNullBooleanField("check", nil),
+	))
+	form := Form()
+	html := strings.TrimSpace(form.Html())
+	if html != `<input type="checkbox" name="check">` {
+		t.Errorf(`Incorrect HTML rendered for default null boolean field: %s`, html)
+		return
+	}
+}
+
+func TestNullBooleanFieldInitialFalseRender(t *testing.T) {
+	Form := DefineForm(NewFields(
+		NewNullBooleanField("check", nil),
+	))
+	form := Form()
+	field, _ := form.GetField("check")
+	field.SetInitial("false")
+	html := strings.TrimSpace(form.Html())
+	if html != `<input type="checkbox" name="check">` {
+		t.Errorf(`Incorrect HTML rendered for SetInitial("false") null boolean field: %s`, html)
+		return
+	}
+}
+
+func TestNullBooleanFieldInitialTrueRender(t *testing.T) {
+	Form := DefineForm(NewFields(
+		NewNullBooleanField("check", nil),
+	))
+	form := Form()
+	field, _ := form.GetField("check")
+	field.SetInitial("true")
+	html := strings.TrimSpace(form.Html())
+	if html != `<input type="checkbox" name="check" checked>` {
+		t.Errorf(`Incorrect HTML rendered for SetInitial("true") null boolean field: %s`, html)
+		return
+	}
+}
\ No newline at end of file