diff --git a/src/mscorlib/shared/System/Security/SecurityException.cs b/src/mscorlib/shared/System/Security/SecurityException.cs
index 9010652a7295..86e3cd463181 100644
--- a/src/mscorlib/shared/System/Security/SecurityException.cs
+++ b/src/mscorlib/shared/System/Security/SecurityException.cs
@@ -62,16 +62,5 @@ protected SecurityException(SerializationInfo info, StreamingContext context)
         public object PermitOnlySetInstance { get; set; }
         public string RefusedSet { get; set; }
         public string Url { get; set; }
-        public SecurityZone Zone { get; set; }
-    }
-
-    public enum SecurityZone
-    {
-        MyComputer   = 0,
-        Intranet     = 1,
-        Trusted      = 2,
-        Internet     = 3,
-        Untrusted    = 4,
-        NoZone       = -1
     }
 }