diff --git a/src/decorator/common/IsOptional.ts b/src/decorator/common/IsOptional.ts
index 38204c5659..1c4d26a077 100644
--- a/src/decorator/common/IsOptional.ts
+++ b/src/decorator/common/IsOptional.ts
@@ -18,7 +18,7 @@ export function IsOptional(validationOptions?: ValidationOptions): PropertyDecor
       propertyName: propertyName,
       constraints: [
         (object: any, value: any): boolean => {
-          return object[propertyName] !== null && object[propertyName] !== undefined;
+          return propertyName in object;
         },
       ],
       validationOptions: validationOptions,