diff --git a/Source/OCMock/OCMConstraint.h b/Source/OCMock/OCMConstraint.h
index da293796..57116c5c 100644
--- a/Source/OCMock/OCMConstraint.h
+++ b/Source/OCMock/OCMConstraint.h
@@ -70,7 +70,8 @@
 	BOOL (^block)(id);
 }
 
-- (instancetype)initWithConstraintBlock:(BOOL (^)(id))block;
+- (instancetype)initWithConstraintBlock:(BOOL (^)(id))block NS_DESIGNATED_INITIALIZER;
+- (instancetype)init NS_UNAVAILABLE;
 
 @end