diff --git a/src/Microsoft.AspNetCore.Server.IISIntegration.Tools/WebConfigTransform.cs b/src/Microsoft.AspNetCore.Server.IISIntegration.Tools/WebConfigTransform.cs
index 9945650008..563e2a00eb 100644
--- a/src/Microsoft.AspNetCore.Server.IISIntegration.Tools/WebConfigTransform.cs
+++ b/src/Microsoft.AspNetCore.Server.IISIntegration.Tools/WebConfigTransform.cs
@@ -61,23 +61,11 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.Tools
             // replaced with backwards slashes when the application is published on a non-Windows machine
             var appPath = Path.Combine(".", appName).Replace("/", "\\");
             var logPath = Path.Combine(configureForAzure ? @"\\?\%home%\LogFiles" : @".\logs", "stdout").Replace("/", "\\");
+            RemoveLauncherArgs(aspNetCoreElement);
 
             if (!isPortable)
             {
                 aspNetCoreElement.SetAttributeValue("processPath", appPath);
-                var arguments = (string)aspNetCoreElement.Attribute("arguments");
-
-                if (arguments != null)
-                {
-                    const string launcherArgs = "%LAUNCHER_ARGS%";
-                    var position = 0;
-                    while ((position = arguments.IndexOf(launcherArgs, position, StringComparison.OrdinalIgnoreCase)) >= 0)
-                    {
-                        arguments = arguments.Remove(position, launcherArgs.Length);
-                    }
-
-                    aspNetCoreElement.SetAttributeValue("arguments", arguments.Trim());
-                }
             }
             else
             {
@@ -85,10 +73,12 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.Tools
 
                 // In Xml the order of attributes does not matter but it is nice to have
                 // the `arguments` attribute next to the `processPath` attribute
-                aspNetCoreElement.Attribute("arguments")?.Remove();
+                var argumentsAttribute = aspNetCoreElement.Attribute("arguments");
+                argumentsAttribute?.Remove();
                 var attributes = aspNetCoreElement.Attributes().ToList();
                 var processPathIndex = attributes.FindIndex(a => a.Name.LocalName == "processPath");
-                attributes.Insert(processPathIndex + 1, new XAttribute("arguments", appPath));
+                attributes.Insert(processPathIndex + 1,
+                    new XAttribute("arguments", (appPath + " " + (string)argumentsAttribute).Trim()));
 
                 aspNetCoreElement.Attributes().Remove();
                 aspNetCoreElement.Add(attributes);
@@ -113,5 +103,22 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.Tools
         {
             element.SetAttributeValue(attributeName, (string)element.Attribute(attributeName) ?? value);
         }
+
+        private static void RemoveLauncherArgs(XElement aspNetCoreElement)
+        {
+            var arguments = (string)aspNetCoreElement.Attribute("arguments");
+
+            if (arguments != null)
+            {
+                const string launcherArgs = "%LAUNCHER_ARGS%";
+                var position = 0;
+                while ((position = arguments.IndexOf(launcherArgs, position, StringComparison.OrdinalIgnoreCase)) >= 0)
+                {
+                    arguments = arguments.Remove(position, launcherArgs.Length);
+                }
+
+                aspNetCoreElement.SetAttributeValue("arguments", arguments.Trim());
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/test/Microsoft.AspNetCore.Server.IISIntegration.Tools.Tests/WebConfigTransformFacts.cs b/test/Microsoft.AspNetCore.Server.IISIntegration.Tools.Tests/WebConfigTransformFacts.cs
index 1351f88fc3..bc471ba766 100644
--- a/test/Microsoft.AspNetCore.Server.IISIntegration.Tools.Tests/WebConfigTransformFacts.cs
+++ b/test/Microsoft.AspNetCore.Server.IISIntegration.Tools.Tests/WebConfigTransformFacts.cs
@@ -186,22 +186,6 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.Tools.Tests
                 aspNetCoreElement));
         }
 
-        [Fact]
-        public void WebConfigTransform_overwrites_existing_arguments_attribute_for_portable_apps()
-        {
-            var input = WebConfigTemplate;
-            input.Descendants("aspNetCore").Single().SetAttributeValue("arguments", "42");
-
-            var aspNetCoreElement =
-                WebConfigTransform.Transform(input, "test.exe", configureForAzure: false, isPortable: true)
-                    .Descendants("aspNetCore").Single();
-
-            Assert.True(XNode.DeepEquals(
-                XDocument.Parse(@"<aspNetCore processPath=""dotnet"" arguments="".\test.exe"" stdoutLogEnabled=""false""
-                     stdoutLogFile="".\logs\stdout"" />").Root,
-                aspNetCoreElement));
-        }
-
         [Theory]
         [InlineData("%LAUNCHER_ARGS%", "")]
         [InlineData(" %launcher_ARGS%", "")]
@@ -224,6 +208,29 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.Tools.Tests
             Assert.Equal(outputArguments, (string)aspNetCoreElement.Attribute("arguments"));
         }
 
+        [Theory]
+        [InlineData("", ".\\myapp.dll")]
+        [InlineData("%LAUNCHER_ARGS%", ".\\myapp.dll")]
+        [InlineData("%LAUNCHER_ARGS% %launcher_args%", ".\\myapp.dll")]
+        [InlineData("-my-switch", ".\\myapp.dll -my-switch")]
+        [InlineData(" %launcher_args% -my-switch", ".\\myapp.dll -my-switch")]
+        [InlineData("-my-switch %LaUnChEr_ArGs%", ".\\myapp.dll -my-switch")]
+        [InlineData("-switch-1 -switch-2", ".\\myapp.dll -switch-1 -switch-2")]
+        [InlineData("-switch-1 %LAUNCHER_ARGS% -switch-2", ".\\myapp.dll -switch-1  -switch-2")]
+        [InlineData("%LAUNCHER_ARGS% -switch %launcher_args%", ".\\myapp.dll -switch")]
+        public void WebConfigTransform_wont_override_existing_args_for_portable_apps(string inputArguments, string outputArguments)
+        {
+            var input = WebConfigTemplate;
+            input.Descendants("aspNetCore").Single().SetAttributeValue("arguments", inputArguments);
+
+            var aspNetCoreElement =
+                WebConfigTransform.Transform(input, "myapp.dll", configureForAzure: false, isPortable: true)
+                    .Descendants("aspNetCore").Single();
+
+            Assert.Equal(outputArguments, (string)aspNetCoreElement.Attribute("arguments"));
+        }
+
+
         private bool VerifyMissingElementCreated(params string[] elementNames)
         {
             var input = WebConfigTemplate;