diff --git a/lib/compile/rules.js b/lib/compile/rules.js
index 271b343d2..68195f75e 100644
--- a/lib/compile/rules.js
+++ b/lib/compile/rules.js
@@ -7,7 +7,7 @@ module.exports = function rules() {
   var RULES = [
     { type: 'number',
       rules: [ { 'maximum': ['exclusiveMaximum'] },
-               { 'minimum': ['exclusiveMinimum'] }, 'multipleOf'] },
+               { 'minimum': ['exclusiveMinimum'] }, 'multipleOf', 'format'] },
     { type: 'string',
       rules: [ 'maxLength', 'minLength', 'pattern', 'format' ] },
     { type: 'array',
diff --git a/lib/dot/definitions.def b/lib/dot/definitions.def
index 99002bb7d..bb40d18c9 100644
--- a/lib/dot/definitions.def
+++ b/lib/dot/definitions.def
@@ -2,6 +2,7 @@
   {{
     var $lvl = it.level;
     var $dataLvl = it.dataLevel;
+    var $type = it.schema.type || '';
     var $schema = it.schema[$keyword];
     var $schemaPath = it.schemaPath + it.util.getProperty($keyword);
     var $errSchemaPath = it.errSchemaPath + '/' + $keyword;
diff --git a/lib/dot/format.jst b/lib/dot/format.jst
index 590e4956e..b2894611e 100644
--- a/lib/dot/format.jst
+++ b/lib/dot/format.jst
@@ -77,11 +77,15 @@
     var $isObject = typeof $format == 'object'
                     && !($format instanceof RegExp)
                     && $format.validate;
+    var $types = $isObject && $format.types || ['string'];
     if ($isObject) {
       var $async = $format.async === true;
       $format = $format.validate;
     }
   }}
+  {{? $types.indexOf($type) === -1 }}
+    {{# def.skipFormat }}
+  {{?}}
   {{? $async }}
     {{
       if (!it.async) throw new Error('async format in sync schema');
diff --git a/spec/ajv.spec.js b/spec/ajv.spec.js
index 73d09c108..71785f24e 100644
--- a/spec/ajv.spec.js
+++ b/spec/ajv.spec.js
@@ -386,27 +386,71 @@ describe('Ajv', function () {
 
 
   describe('addFormat method', function() {
-    it('should add format as regular expression', function() {
-      ajv.addFormat('identifier', /^[a-z_$][a-z0-9_$]*$/i);
-      testFormat();
-    });
+    describe.skip('without any type restrictions specified', function() {
+      it('should add format as regular expression', function() {
+        ajv.addFormat('identifier', /^[a-z_$][a-z0-9_$]*$/i);
+        testFormat();
+      });
 
-    it('should add format as string', function() {
-      ajv.addFormat('identifier', '^[A-Za-z_$][A-Za-z0-9_$]*$');
-      testFormat();
-    });
+      it('should add format as string', function() {
+        ajv.addFormat('identifier', '^[A-Za-z_$][A-Za-z0-9_$]*$');
+        testFormat();
+      });
+
+      it('should add format as function', function() {
+        ajv.addFormat('identifier', function (str) { return /^[a-z_$][a-z0-9_$]*$/i.test(str); });
+        testFormat();
+      });
 
-    it('should add format as function', function() {
-      ajv.addFormat('identifier', function (str) { return /^[a-z_$][a-z0-9_$]*$/i.test(str); });
-      testFormat();
+      it('should add format as object', function() {
+        ajv.addFormat('identifier', {
+          validate: function (str) { return /^[a-z_$][a-z0-9_$]*$/i.test(str); },
+        });
+        testFormat();
+      });
+
+      function testFormat() {
+        var validate = ajv.compile({ format: 'identifier' });
+        validate('Abc1') .should.equal(true);
+        validate('123') .should.equal(false);
+        validate(123) .should.equal(true);
+      }
     });
 
-    function testFormat() {
-      var validate = ajv.compile({ format: 'identifier' });
-      validate('Abc1') .should.equal(true);
-      validate('123') .should.equal(false);
-      validate(123) .should.equal(true);
-    }
+    describe('with type restrictions specified', function() {
+      it('should apply the format to the type specified', function() {
+
+        ajv.addFormat('positive', {
+          types: ['number'],
+          validate: function(x) {
+            return x >= 0;
+          }
+        });
+
+        var validate = ajv.compile({
+          type: 'number',
+          format: 'positive'
+        });
+        validate(-12.3) .should.equal(false);
+        validate(12.3) .should.equal(true);
+      });
+
+      it('should not fail types not specified', function() {
+        ajv.addFormat('positive', {
+          types: ['number'],
+          validate: function(x) {
+            return x >= 0;
+          }
+        });
+
+        var validate = ajv.compile({
+          type: 'string',
+          format: 'positive'
+        });
+        validate('Abc1') .should.equal(true);
+      });
+
+    });
   });