diff --git a/src/Generator/Generators/CLI/CLISourcesTemplate.cs b/src/Generator/Generators/CLI/CLISourcesTemplate.cs
index 3feaf045..a3e233a7 100644
--- a/src/Generator/Generators/CLI/CLISourcesTemplate.cs
+++ b/src/Generator/Generators/CLI/CLISourcesTemplate.cs
@@ -1067,7 +1067,10 @@ namespace CppSharp.Generators.CLI
                 var typePrinter = new CppTypePrinter(Driver.TypeDatabase);
                 var type = paramType.Visit(typePrinter);
 
-                WriteLine("{0} {1};", type, argName);
+                if (param.IsInOut)
+                    WriteLine("{0} {1} = {2};", type, argName, param.Name);
+                else
+                    WriteLine("{0} {1};", type, argName);
             }
             else
             {
diff --git a/src/Generator/Generators/CSharp/CSharpMarshal.cs b/src/Generator/Generators/CSharp/CSharpMarshal.cs
index da536cd2..6866c8bd 100644
--- a/src/Generator/Generators/CSharp/CSharpMarshal.cs
+++ b/src/Generator/Generators/CSharp/CSharpMarshal.cs
@@ -474,9 +474,12 @@ namespace CppSharp.Generators.CSharp
                 {
                     var typeName = Type.TypePrinterDelegate(pointee);
 
-                    Context.SupportBefore.WriteLine("{0} _{1};", typeName, param.Name);
-                    Context.Return.Write("&_{0}", param.Name);
+                    if (param.IsInOut)
+                        Context.SupportBefore.WriteLine("{0} _{1} = {1};", typeName, param.Name);
+                    else
+                        Context.SupportBefore.WriteLine("{0} _{1};", typeName, param.Name);
 
+                    Context.Return.Write("&_{0}", param.Name);
                 }
                 else
                     Context.Return.Write(Helpers.SafeIdentifier(Context.Parameter.Name));
diff --git a/src/Generator/Generators/CSharp/CSharpTextTemplate.cs b/src/Generator/Generators/CSharp/CSharpTextTemplate.cs
index 3d003ecb..062745db 100644
--- a/src/Generator/Generators/CSharp/CSharpTextTemplate.cs
+++ b/src/Generator/Generators/CSharp/CSharpTextTemplate.cs
@@ -2503,7 +2503,7 @@ namespace CppSharp.Generators.CSharp
                 case ParameterUsage.Out:
                     return "out ";
                 case ParameterUsage.InOut:
-                    return "ref";
+                    return "ref ";
                 default:
                     return string.Empty;
             }
diff --git a/tests/Basic/Basic.Tests.cs b/tests/Basic/Basic.Tests.cs
index dcf25e84..aa3df3b7 100644
--- a/tests/Basic/Basic.Tests.cs
+++ b/tests/Basic/Basic.Tests.cs
@@ -77,6 +77,26 @@ public class BasicTests : GeneratorTestFixture
         Assert.That(f, Is.EqualTo(10.0f));
     }
 
+    [Test]
+    public void TestPrimitiveInOutParameters()
+    {
+        var hello = new Hello();
+
+        int i = 10;
+        Assert.That(hello.TestPrimitiveInOut(ref i), Is.True);
+        Assert.That(i, Is.EqualTo(20));
+    }
+
+    [Test]
+    public void TestPrimitiveInOutRefParameters()
+    {
+        var hello = new Hello();
+
+        int i = 10;
+        Assert.That(hello.TestPrimitiveInOutRef(ref i), Is.True);
+        Assert.That(i, Is.EqualTo(20));
+    }
+
     [Test]
     public void TestNullRef()
     {
diff --git a/tests/Basic/Basic.cpp b/tests/Basic/Basic.cpp
index 48547de4..90e9d7d3 100644
--- a/tests/Basic/Basic.cpp
+++ b/tests/Basic/Basic.cpp
@@ -169,6 +169,18 @@ bool Hello::TestPrimitiveOutRef(CS_OUT float& f)
     return true;
 }
 
+bool Hello::TestPrimitiveInOut(CS_IN_OUT int* i)
+{
+    *i += 10;
+    return true;
+}
+
+bool Hello::TestPrimitiveInOutRef(CS_IN_OUT int& i)
+{
+    i += 10;
+    return true;
+}
+
 int unsafeFunction(const Bar& ret, char* testForString, void (*foo)(int))
 {
     return ret.A;
diff --git a/tests/Basic/Basic.cs b/tests/Basic/Basic.cs
index fbf14581..f5dd6e32 100644
--- a/tests/Basic/Basic.cs
+++ b/tests/Basic/Basic.cs
@@ -31,6 +31,8 @@ namespace CppSharp.Tests
             ctx.SetClassAsValueType("Bar2");
             ctx.SetMethodParameterUsage("Hello", "TestPrimitiveOut", 1, ParameterUsage.Out);
             ctx.SetMethodParameterUsage("Hello", "TestPrimitiveOutRef", 1, ParameterUsage.Out);
+            ctx.SetMethodParameterUsage("Hello", "TestPrimitiveInOut", 1, ParameterUsage.InOut);
+            ctx.SetMethodParameterUsage("Hello", "TestPrimitiveInOutRef", 1, ParameterUsage.InOut);
         }
 
         public static void Main(string[] args)
diff --git a/tests/Basic/Basic.h b/tests/Basic/Basic.h
index cebe6778..de936323 100644
--- a/tests/Basic/Basic.h
+++ b/tests/Basic/Basic.h
@@ -123,6 +123,9 @@ public:
 
     bool TestPrimitiveOut(CS_OUT float* f);
     bool TestPrimitiveOutRef(CS_OUT float& f);
+
+    bool TestPrimitiveInOut(CS_IN_OUT int* i);
+    bool TestPrimitiveInOutRef(CS_IN_OUT int& i);
 };
 
 class DLL_API AbstractFoo
diff --git a/tests/Tests.h b/tests/Tests.h
index 1b493c67..1c2cbaf2 100644
--- a/tests/Tests.h
+++ b/tests/Tests.h
@@ -22,4 +22,5 @@
 #endif
 #endif
 
-#define CS_OUT
\ No newline at end of file
+#define CS_OUT
+#define CS_IN_OUT
\ No newline at end of file