diff --git a/lib/cmock_generator_plugin_return_thru_ptr.rb b/lib/cmock_generator_plugin_return_thru_ptr.rb
index 9321559..96b2003 100644
--- a/lib/cmock_generator_plugin_return_thru_ptr.rb
+++ b/lib/cmock_generator_plugin_return_thru_ptr.rb
@@ -14,7 +14,7 @@ class CMockGeneratorPluginReturnThruPtr
 
       lines << "  char ReturnThruPtr_#{arg[:name]}_Used;\n"
       lines << "  #{arg[:type]} ReturnThruPtr_#{arg[:name]}_Val;\n"
-      lines << "  int ReturnThruPtr_#{arg[:name]}_Size;\n"
+      lines << "  size_t ReturnThruPtr_#{arg[:name]}_Size;\n"
     end
     lines
   end
@@ -33,10 +33,10 @@ class CMockGeneratorPluginReturnThruPtr
                  " #{function[:name]}_CMockReturnMemThruPtr_#{arg[:name]}(__LINE__, #{arg[:name]}, sizeof(*#{arg[:name]}))\n"
                end
       lines << "#define #{function[:name]}_ReturnArrayThruPtr_#{arg[:name]}(#{arg[:name]}, cmock_len)"
-      lines << " #{function[:name]}_CMockReturnMemThruPtr_#{arg[:name]}(__LINE__, #{arg[:name]}, (int)(cmock_len * (int)sizeof(*#{arg[:name]})))\n"
+      lines << " #{function[:name]}_CMockReturnMemThruPtr_#{arg[:name]}(__LINE__, #{arg[:name]}, cmock_len * sizeof(*#{arg[:name]}))\n"
       lines << "#define #{function[:name]}_ReturnMemThruPtr_#{arg[:name]}(#{arg[:name]}, cmock_size)"
       lines << " #{function[:name]}_CMockReturnMemThruPtr_#{arg[:name]}(__LINE__, #{arg[:name]}, cmock_size)\n"
-      lines << "void #{function[:name]}_CMockReturnMemThruPtr_#{arg[:name]}(UNITY_LINE_TYPE cmock_line, #{arg[:type]} #{arg[:name]}, int cmock_size);\n"
+      lines << "void #{function[:name]}_CMockReturnMemThruPtr_#{arg[:name]}(UNITY_LINE_TYPE cmock_line, #{arg[:type]} #{arg[:name]}, size_t cmock_size);\n"
     end
     lines
   end
@@ -48,7 +48,7 @@ class CMockGeneratorPluginReturnThruPtr
       arg_name = arg[:name]
       next unless @utils.ptr_or_str?(arg[:type]) && !(arg[:const?])
 
-      lines << "void #{func_name}_CMockReturnMemThruPtr_#{arg_name}(UNITY_LINE_TYPE cmock_line, #{arg[:type]} #{arg_name}, int cmock_size)\n"
+      lines << "void #{func_name}_CMockReturnMemThruPtr_#{arg_name}(UNITY_LINE_TYPE cmock_line, #{arg[:type]} #{arg_name}, size_t cmock_size)\n"
       lines << "{\n"
       lines << "  CMOCK_#{func_name}_CALL_INSTANCE* cmock_call_instance = " \
                "(CMOCK_#{func_name}_CALL_INSTANCE*)CMock_Guts_GetAddressFor(CMock_Guts_MemEndOfChain(Mock.#{func_name}_CallInstance));\n"
diff --git a/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb b/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb
index 3c8b075..03fc5e4 100644
--- a/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb
+++ b/test/unit/cmock_generator_plugin_return_thru_ptr_test.rb
@@ -73,7 +73,7 @@ describe CMockGeneratorPluginReturnThruPtr, "Verify CMockGeneratorPluginReturnTh
     complex_func_expect()
     expected = "  char ReturnThruPtr_tofu_Used;\n" +
                "  int* ReturnThruPtr_tofu_Val;\n" +
-               "  int ReturnThruPtr_tofu_Size;\n"
+               "  size_t ReturnThruPtr_tofu_Size;\n"
     returned = @cmock_generator_plugin_return_thru_ptr.instance_typedefs(@complex_func)
     assert_equal(expected, returned)
   end
@@ -91,10 +91,10 @@ describe CMockGeneratorPluginReturnThruPtr, "Verify CMockGeneratorPluginReturnTh
       "#define Pine_ReturnThruPtr_tofu(tofu)" +
       " Pine_CMockReturnMemThruPtr_tofu(__LINE__, tofu, sizeof(int))\n" +
       "#define Pine_ReturnArrayThruPtr_tofu(tofu, cmock_len)" +
-      " Pine_CMockReturnMemThruPtr_tofu(__LINE__, tofu, (int)(cmock_len * (int)sizeof(*tofu)))\n" +
+      " Pine_CMockReturnMemThruPtr_tofu(__LINE__, tofu, cmock_len * sizeof(*tofu))\n" +
       "#define Pine_ReturnMemThruPtr_tofu(tofu, cmock_size)" +
       " Pine_CMockReturnMemThruPtr_tofu(__LINE__, tofu, cmock_size)\n" +
-      "void Pine_CMockReturnMemThruPtr_tofu(UNITY_LINE_TYPE cmock_line, int* tofu, int cmock_size);\n"
+      "void Pine_CMockReturnMemThruPtr_tofu(UNITY_LINE_TYPE cmock_line, int* tofu, size_t cmock_size);\n"
 
     returned = @cmock_generator_plugin_return_thru_ptr.mock_function_declarations(@complex_func)
     assert_equal(expected, returned)
@@ -104,7 +104,7 @@ describe CMockGeneratorPluginReturnThruPtr, "Verify CMockGeneratorPluginReturnTh
     complex_func_expect();
 
     expected =
-      "void Pine_CMockReturnMemThruPtr_tofu(UNITY_LINE_TYPE cmock_line, int* tofu, int cmock_size)\n" +
+      "void Pine_CMockReturnMemThruPtr_tofu(UNITY_LINE_TYPE cmock_line, int* tofu, size_t cmock_size)\n" +
       "{\n" +
       "  CMOCK_Pine_CALL_INSTANCE* cmock_call_instance = " +
       "(CMOCK_Pine_CALL_INSTANCE*)CMock_Guts_GetAddressFor(CMock_Guts_MemEndOfChain(Mock.Pine_CallInstance));\n" +