diff --git a/lib/validatable.js b/lib/validatable.js
index 686507c7..54bcce2a 100644
--- a/lib/validatable.js
+++ b/lib/validatable.js
@@ -9,6 +9,7 @@ Validatable.validatesLengthOf = getConfigurator('length');
 Validatable.validatesNumericalityOf = getConfigurator('numericality');
 Validatable.validatesInclusionOf = getConfigurator('inclusion');
 Validatable.validatesExclusionOf = getConfigurator('exclusion');
+Validatable.validatesFormatOf = getConfigurator('format');
 
 function getConfigurator(name) {
     return function () {
@@ -96,6 +97,24 @@ var defaultMessages = {
     exclusion: 'is reserved'
 };
 
+function nullCheck(attr, conf, err) {
+    var isNull = this[attr] === null || !(attr in this);
+    if (isNull) {
+        if (!conf.allowNull) {
+            err('null');
+        }
+        return true;
+    } else {
+        if (blank(this[attr])) {
+            if (!conf.allowBlank) {
+                err('blank');
+            }
+            return true;
+        }
+    }
+    return false;
+}
+
 var validators = {
     presence: function (attr, conf, err) {
         if (blank(this[attr])) {
@@ -103,22 +122,8 @@ var validators = {
         }
     },
     length: function (attr, conf, err) {
-        var isNull = this[attr] === null || !(attr in this);
-        if (isNull) {
-            if (conf.allowNull) {
-                return true;
-            } else {
-                return err('null');
-            }
-        } else {
-            if (blank(this[attr])) {
-                if (conf.allowBlank) {
-                    return true;
-                } else {
-                    return err('blank');
-                }
-            }
-        }
+        if (nullCheck.call(this, attr, conf, err)) return;
+
         var len = this[attr].length;
         if (conf.min && len < conf.min) {
             err('min');
@@ -131,6 +136,8 @@ var validators = {
         }
     },
     numericality: function (attr, conf, err) {
+        if (nullCheck.call(this, attr, conf, err)) return;
+
         if (typeof this[attr] !== 'number') {
             return err('number');
         }
@@ -139,14 +146,29 @@ var validators = {
         }
     },
     inclusion: function (attr, conf, err) {
+        if (nullCheck.call(this, attr, conf, err)) return;
+
         if (!~conf.in.indexOf(this[attr])) {
             err()
         }
     },
     exclusion: function (attr, conf, err) {
+        if (nullCheck.call(this, attr, conf, err)) return;
+
         if (~conf.in.indexOf(this[attr])) {
             err()
         }
+    },
+    format: function (attr, conf, err) {
+        if (nullCheck.call(this, attr, conf, err)) return;
+
+        if (typeof this[attr] === 'string') {
+            if (!this[attr].match(conf['with'])) {
+                err();
+            }
+        } else {
+            err();
+        }
     }
 };
 
diff --git a/test/validations_test.coffee b/test/validations_test.coffee
index bba9af2b..aeba758f 100644
--- a/test/validations_test.coffee
+++ b/test/validations_test.coffee
@@ -151,7 +151,7 @@ it 'should validate inclusion', (test) ->
     user.gender = 'male'
     test.ok user.isValid()
 
-    user.gender = ''
+    user.gender = 'man'
     test.ok not user.isValid()
     test.equal user.errors.gender[0], 'is not included in the list'
 
@@ -170,3 +170,15 @@ it 'should validate exclusion', (test) ->
 
     test.done()
 
+it 'should validate format', (test) ->
+    User.validatesFormatOf 'email', with: /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i
+    user = new User validAttributes
+
+    user.email = 'invalid email'
+    test.ok not user.isValid()
+
+    user.email = 'valid@email.tld'
+    test.ok user.isValid()
+
+    test.done()
+