diff --git a/src/lib/isURL.js b/src/lib/isURL.js
index 7f6e0ba5f..253b3098c 100644
--- a/src/lib/isURL.js
+++ b/src/lib/isURL.js
@@ -136,7 +136,7 @@ export default function isURL(url, options) {
     }
   }
 
-  if (port_str !== null) {
+  if (port_str !== null && port_str.length > 0) {
     port = parseInt(port_str, 10);
     if (!/^[0-9]+$/.test(port_str) || port <= 0 || port > 65535) {
       return false;
diff --git a/test/validators.js b/test/validators.js
index 279796869..a5e975884 100644
--- a/test/validators.js
+++ b/test/validators.js
@@ -535,6 +535,31 @@ describe('Validators', () => {
     });
   });
 
+  it('should validate URLs with column and no port', () => {
+    test({
+      validator: 'isURL',
+      valid: [
+        'http://example.com:',
+        'ftp://example.com:',
+      ],
+      invalid: [
+        'https://example.com:abc',
+      ],
+    });
+  });
+
+  it('should validate sftp protocol URL containing column and no port', () => {
+    test({
+      validator: 'isURL',
+      args: [{
+        protocols: ['sftp'],
+      }],
+      valid: [
+        'sftp://user:pass@terminal.aws.test.nl:/incoming/things.csv',
+      ],
+    });
+  });
+
   it('should validate protocol relative URLs', () => {
     test({
       validator: 'isURL',