diff --git a/types/validator/index.d.ts b/types/validator/index.d.ts
index 0806d34f2a..204b032ba5 100644
--- a/types/validator/index.d.ts
+++ b/types/validator/index.d.ts
@@ -175,9 +175,6 @@ declare namespace ValidatorJS {
     // check if the string contains one or more multibyte chars.
     isMultibyte(str: string): boolean;
 
-    // check if the string is null.
-    isNull(str: string): boolean;
-
     // check if the string contains only numbers.
     isNumeric(str: string): boolean;
 
@@ -615,11 +612,6 @@ declare module "validator/lib/isMultibyte" {
   export = isMultibyte;
 }
 
-declare module "validator/lib/isNull" {
-  const isNull: typeof validator.isNull;
-  export = isNull;
-}
-
 declare module "validator/lib/isNumeric" {
   const isNumeric: typeof validator.isNumeric;
   export = isNumeric;
diff --git a/types/validator/validator-tests.ts b/types/validator/validator-tests.ts
index 0aaf7f1f10..c3d4327d84 100644
--- a/types/validator/validator-tests.ts
+++ b/types/validator/validator-tests.ts
@@ -50,7 +50,6 @@ import isMimeTypeFunc = require('validator/lib/isMimeType');
 import isMobilePhoneFunc = require('validator/lib/isMobilePhone');
 import isMongoIdFunc = require('validator/lib/isMongoId');
 import isMultibyteFunc = require('validator/lib/isMultibyte');
-import isNullFunc = require('validator/lib/isNull');
 import isNumericFunc = require('validator/lib/isNumeric');
 import isPortFunc = require('validator/lib/isPort');
 import isPostalCodeFunc = require('validator/lib/isPostalCode');
@@ -209,9 +208,6 @@ import whitelistFunc = require('validator/lib/whitelist');
   let _isMultibyte = validator.isMultibyte;
   _isMultibyte = isMultibyteFunc;
 
-  let _isNull = validator.isNull;
-  _isNull = isNullFunc;
-
   let _isNumeric = validator.isNumeric;
   _isNumeric = isNumericFunc;
 
@@ -568,8 +564,6 @@ let any: any;
 
   result = validator.isMultibyte('sample');
 
-  result = validator.isNull('sample');
-
   result = validator.isNumeric('sample');
 
   result = validator.isPort('sample');