diff --git a/Mono.Cecil/MethodCallingConvention.cs b/Mono.Cecil/MethodCallingConvention.cs
index f9c0e0c95..80f3e9773 100644
--- a/Mono.Cecil/MethodCallingConvention.cs
+++ b/Mono.Cecil/MethodCallingConvention.cs
@@ -17,6 +17,7 @@ public enum MethodCallingConvention : byte {
 		ThisCall	= 0x3,
 		FastCall	= 0x4,
 		VarArg		= 0x5,
+		Unmanaged	= 0x9,
 		Generic		= 0x10,
 	}
 }