diff --git a/mcs/class/corlib/ReferenceSources/RuntimeType.cs b/mcs/class/corlib/ReferenceSources/RuntimeType.cs
index ce498cb17c52d..bedcf1af0c14a 100644
--- a/mcs/class/corlib/ReferenceSources/RuntimeType.cs
+++ b/mcs/class/corlib/ReferenceSources/RuntimeType.cs
@@ -602,6 +602,12 @@ bool IsGenericCOMObjectImpl ()
 			get;
 		}
 
+#if MOBILE
+		static int get_core_clr_security_level ()
+		{
+			return 1;
+		}
+#else
 		//seclevel { transparent = 0, safe-critical = 1, critical = 2}
 		[MethodImplAttribute(MethodImplOptions.InternalCall)]
 		public extern int get_core_clr_security_level ();
@@ -616,6 +622,7 @@ bool IsGenericCOMObjectImpl ()
 
 		public override bool IsSecuritySafeCritical {
 			get { return get_core_clr_security_level () == 1; }
-		}		
+		}
+#endif
 	}
 }
diff --git a/mcs/class/corlib/System.Reflection/MonoField.cs b/mcs/class/corlib/System.Reflection/MonoField.cs
index 8c6f92469380c..ef2180fed03d6 100644
--- a/mcs/class/corlib/System.Reflection/MonoField.cs
+++ b/mcs/class/corlib/System.Reflection/MonoField.cs
@@ -296,6 +296,12 @@ internal MonoField Clone (string newName)
 				throw new InvalidOperationException ("Late bound operations cannot be performed on fields with types for which Type.ContainsGenericParameters is true.");
 	    }
 
+#if MOBILE
+		static int get_core_clr_security_level ()
+		{
+			return 1;
+		}
+#else
 		//seclevel { transparent = 0, safe-critical = 1, critical = 2}
 		[MethodImplAttribute(MethodImplOptions.InternalCall)]
 		public extern int get_core_clr_security_level ();
@@ -311,5 +317,6 @@ internal MonoField Clone (string newName)
 		public override bool IsSecuritySafeCritical {
 			get { return get_core_clr_security_level () == 1; }
 		}
+#endif
 	}
 }
diff --git a/mcs/class/corlib/System.Reflection/MonoMethod.cs b/mcs/class/corlib/System.Reflection/MonoMethod.cs
index 1c0e73c485f4a..04c0c56708632 100644
--- a/mcs/class/corlib/System.Reflection/MonoMethod.cs
+++ b/mcs/class/corlib/System.Reflection/MonoMethod.cs
@@ -502,9 +502,16 @@ public override MethodInfo GetGenericMethodDefinition ()
 			return CustomAttributeData.GetCustomAttributes (this);
 		}
 
+#if MOBILE
+		static int get_core_clr_security_level ()
+		{
+			return 1;
+		}
+#else
 		//seclevel { transparent = 0, safe-critical = 1, critical = 2}
 		[MethodImplAttribute(MethodImplOptions.InternalCall)]
 		public extern int get_core_clr_security_level ();
+#endif
 
 		public override bool IsSecurityTransparent {
 			get { return get_core_clr_security_level () == 0; }
@@ -752,8 +759,15 @@ public override Object Invoke (BindingFlags invokeAttr, Binder binder, Object[]
 			return CustomAttributeData.GetCustomAttributes (this);
 		}
 
+#if MOBILE
+		static int get_core_clr_security_level ()
+		{
+			return 1;
+		}
+#else
 		[MethodImplAttribute(MethodImplOptions.InternalCall)]
 		public extern int get_core_clr_security_level ();
+#endif
 
 		public override bool IsSecurityTransparent {
 			get { return get_core_clr_security_level () == 0; }