diff --git a/es/lib/isIP.js b/es/lib/isIP.js
index db05e7369..9280d8766 100644
--- a/es/lib/isIP.js
+++ b/es/lib/isIP.js
@@ -29,7 +29,7 @@ import assertString from './util/assertString';
    to the 5th link, and "interface10" belongs to the 10th organization.
  * * */
 
-var ipv4Maybe = /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
+var ipv4Maybe = /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/;
 var ipv6Block = /^[0-9A-F]{1,4}$/i;
 export default function isIP(str) {
   var version = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : '';
diff --git a/lib/isIP.js b/lib/isIP.js
index 13f7ebc3f..b5a924cfd 100644
--- a/lib/isIP.js
+++ b/lib/isIP.js
@@ -38,7 +38,7 @@ function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { de
    where the interface "ne0" belongs to the 1st link, "pvc1.3" belongs
    to the 5th link, and "interface10" belongs to the 10th organization.
  * * */
-var ipv4Maybe = /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
+var ipv4Maybe = /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/;
 var ipv6Block = /^[0-9A-F]{1,4}$/i;
 
 function isIP(str) {
diff --git a/src/lib/isIP.js b/src/lib/isIP.js
index 38141760a..a9a805781 100644
--- a/src/lib/isIP.js
+++ b/src/lib/isIP.js
@@ -28,7 +28,7 @@ import assertString from './util/assertString';
    where the interface "ne0" belongs to the 1st link, "pvc1.3" belongs
    to the 5th link, and "interface10" belongs to the 10th organization.
  * * */
-const ipv4Maybe = /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
+const ipv4Maybe = /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/;
 const ipv6Block = /^[0-9A-F]{1,4}$/i;
 
 export default function isIP(str, version = '') {
diff --git a/test/validators.js b/test/validators.js
index f660f0f28..fc9b1446f 100644
--- a/test/validators.js
+++ b/test/validators.js
@@ -734,11 +734,16 @@ describe('Validators', () => {
         '0.0.0.0',
         '255.255.255.255',
         '1.2.3.4',
+        '255.0.0.1',
+        '0.0.1.1',
       ],
       invalid: [
         '::1',
         '2001:db8:0000:1:1:1:1:1',
         '::ffff:127.0.0.1',
+        '137.132.10.01',
+        '0.256.0.256',
+        '255.256.255.256',
       ],
     });
     test({