diff --git a/source/CoreLibrary.nfproj b/source/CoreLibrary.nfproj
index 9a7fdbc2..e8c2cc6f 100644
--- a/source/CoreLibrary.nfproj
+++ b/source/CoreLibrary.nfproj
@@ -21,6 +21,7 @@
     <OutputName>mscorlib</OutputName>
     <IsCoreAssembly>true</IsCoreAssembly>
     <IsMscorlib>true</IsMscorlib>
+    <DefineConstants>$(DefineConstants);NANOCLR_APPDOMAINS</DefineConstants>
     <TargetFrameworkVersion>v1.0</TargetFrameworkVersion>
     <DocumentationFile>bin\$(Configuration)\mscorlib.xml</DocumentationFile>
   </PropertyGroup>
diff --git a/source/System/AppDomain.cs b/source/System/AppDomain.cs
index 9605cbaa..ae7d3044 100644
--- a/source/System/AppDomain.cs
+++ b/source/System/AppDomain.cs
@@ -4,6 +4,12 @@
 // See LICENSE file in the project root for full license information.
 //
 
+///////////////////////////////////////////////////
+// DEV NOTE: to enable the AppDomain API add     //
+// 'NANOCLR_APPDOMAINS' to the compile constants //
+///////////////////////////////////////////////////
+#if (NANOCLR_APPDOMAINS)
+
 using System.Reflection;
 using System.Threading;
 using System.Runtime.CompilerServices;
@@ -113,3 +119,4 @@ public Assembly Load(String assemblyString)
         public static extern void Unload(AppDomain domain);
     }
 }
+#endif // #if (NANOCLR_APPDOMAINS)
diff --git a/source/System/Threading/Thread.cs b/source/System/Threading/Thread.cs
index 94829953..ff694313 100644
--- a/source/System/Threading/Thread.cs
+++ b/source/System/Threading/Thread.cs
@@ -168,11 +168,16 @@ public extern ThreadState ThreadState
             get;
         }
 
+#if (NANOCLR_APPDOMAINS)
+
         /// <summary>
         /// Returns the current domain in which the current thread is running.
         /// </summary>
         /// <returns>An AppDomain representing the current application domain of the running thread.</returns>
         [MethodImpl(MethodImplOptions.InternalCall)]
         public static extern AppDomain GetDomain();
+
+#endif // #if (NANOCLR_APPDOMAINS)
+
     }
 }