diff --git a/src/Geta.NotFoundHandler/Core/Redirects/CustomRedirectCollection.cs b/src/Geta.NotFoundHandler/Core/Redirects/CustomRedirectCollection.cs
index c1f84c5a..adff85fe 100644
--- a/src/Geta.NotFoundHandler/Core/Redirects/CustomRedirectCollection.cs
+++ b/src/Geta.NotFoundHandler/Core/Redirects/CustomRedirectCollection.cs
@@ -222,7 +222,7 @@ private static void BuildPath(
 
         builder.Append(path);
 
-        if (hasAppendSegment && !pathHasTrailingSlash)
+        if (hasAppendSegment && !path.EndsWith("/"))
         {
             builder.Append('/');
         }
diff --git a/tests/Geta.NotFoundHandler.Tests/CustomRedirectCollectionTests.cs b/tests/Geta.NotFoundHandler.Tests/CustomRedirectCollectionTests.cs
index 5e52ba0f..9071569d 100644
--- a/tests/Geta.NotFoundHandler.Tests/CustomRedirectCollectionTests.cs
+++ b/tests/Geta.NotFoundHandler.Tests/CustomRedirectCollectionTests.cs
@@ -399,5 +399,24 @@ public void Find_decodes_plus_sign_correctly()
 
             Assert.Equal(expected, actual.NewUrl); 
         }
+        
+        /// <summary>
+        /// https://github.com/Geta/geta-notfoundhandler/issues/137
+        /// </summary>
+        [Fact]
+        public void Find_does_add_slash_when_new_url_is_missing_trailing_slash()
+        {
+            var collection = new CustomRedirectCollection
+            {
+                new CustomRedirect("/content", "/legacy"),
+            };
+
+            var urlToFind = "/content/file/";
+            var expected = "/legacy/file/";
+
+            var actual = collection.Find(urlToFind.ToUri());
+
+            Assert.Equal(expected, actual.NewUrl);
+        }
     }
 }