diff --git a/CHANGES.rst b/CHANGES.rst
index 795abf2..fb3545b 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -14,7 +14,8 @@ New features:
 
 Bug fixes:
 
-- *add item here*
+- Use zope.interface decorator.
+  [gforcada]
 
 
 1.3.15 (2016-05-25)
diff --git a/plone/app/querystring/indexmodifiers/query_index_modifiers.py b/plone/app/querystring/indexmodifiers/query_index_modifiers.py
index bc03efb..d0fcf1d 100644
--- a/plone/app/querystring/indexmodifiers/query_index_modifiers.py
+++ b/plone/app/querystring/indexmodifiers/query_index_modifiers.py
@@ -1,9 +1,10 @@
 # -*- coding: utf8 -*-
 from dateutil.parser import parse
 from plone.app.querystring.interfaces import IParsedQueryIndexModifier
-from zope.interface import implements
+from zope.interface import implementer
 
 
+@implementer(IParsedQueryIndexModifier)
 class Subject(object):
 
     """
@@ -17,8 +18,6 @@ class Subject(object):
     be removed.
     """
 
-    implements(IParsedQueryIndexModifier)
-
     def __call__(self, value):
         query = value['query']
         # query can be a unicode string or a list of unicode strings.
@@ -42,6 +41,7 @@ def __call__(self, value):
         return ('Subject', value)
 
 
+@implementer(IParsedQueryIndexModifier)
 class base(object):
 
     """
@@ -49,8 +49,6 @@ class base(object):
     see Products.PluginIndexes.DateIndex.DateIndex.DateIndex._convert function
     """
 
-    implements(IParsedQueryIndexModifier)
-
     def __call__(self, value):
         query = value['query']
         if isinstance(query, unicode):
diff --git a/plone/app/querystring/tests/index_testmodifier.py b/plone/app/querystring/tests/index_testmodifier.py
index daa87fe..a36c267 100644
--- a/plone/app/querystring/tests/index_testmodifier.py
+++ b/plone/app/querystring/tests/index_testmodifier.py
@@ -1,35 +1,32 @@
 # -*- coding: utf8 -*-
 
-from zope.interface import implements
+from zope.interface import implementer
 from plone.app.querystring.interfaces import IParsedQueryIndexModifier
 
 
+@implementer(IParsedQueryIndexModifier)
 class SimpleFooIndexModifier(object):
     """Test simple index modifier that do nothing"""
 
-    implements(IParsedQueryIndexModifier)
-
     def __call__(self, value):
         raise Exception("SimpleFooIndexModifier has been called!")
 
 
+@implementer(IParsedQueryIndexModifier)
 class TitleFooIndexModifier(object):
     """Test index modifier that check always Foo"""
 
-    implements(IParsedQueryIndexModifier)
-
     def __call__(self, value):
         return ('Title', 'Foo')
 
 
+@implementer(IParsedQueryIndexModifier)
 class AbstractToDescriptionIndexModifier(object):
     """
     Test index modifier that translate "Abstract" to Description index
     but where value do not count letter "e"
     """
 
-    implements(IParsedQueryIndexModifier)
-
     def __call__(self, value):
         value['query'] = value['query'].replace('e', '')
         return ('Description', value)
diff --git a/plone/app/querystring/tests/testQueryParser.py b/plone/app/querystring/tests/testQueryParser.py
index 809bf49..bf05871 100644
--- a/plone/app/querystring/tests/testQueryParser.py
+++ b/plone/app/querystring/tests/testQueryParser.py
@@ -12,7 +12,7 @@
     NOT_INSTALLED_PLONEAPPQUERYSTRING_INTEGRATION_TESTING
 
 from zope.component import getGlobalSiteManager
-from zope.interface.declarations import implements
+from zope.interface import implementer
 
 import unittest2 as unittest
 
@@ -74,8 +74,8 @@ class MockSiteProperties(object):
     navtree_properties = MockNavtreeProperties()
 
 
+@implementer(INavigationRoot, IPloneSiteRoot)
 class MockSite(object):
-    implements(INavigationRoot, IPloneSiteRoot)
 
     def __init__(self, portal_membership=None):
         self.reference_catalog = MockCatalog()
@@ -88,8 +88,9 @@ def getPhysicalPath(self):
         return ["", MOCK_SITE_ID]
 
 
+@implementer(INavigationRoot)
 class MockNavRoot(MockObject):
-    implements(INavigationRoot)
+    pass
 
 
 class MockUser(object):
diff --git a/plone/app/querystring/tests/testRegistryReader.py b/plone/app/querystring/tests/testRegistryReader.py
index 6db9597..e0f7ba0 100644
--- a/plone/app/querystring/tests/testRegistryReader.py
+++ b/plone/app/querystring/tests/testRegistryReader.py
@@ -1,7 +1,7 @@
 from plone.registry.interfaces import IRegistry
 from plone.registry import Registry
 from zope.component import getGlobalSiteManager
-from zope.interface import implements
+from zope.interface import implementer
 from zope.schema.interfaces import IVocabularyFactory
 from zope.schema.vocabulary import SimpleVocabulary
 
@@ -14,8 +14,8 @@
 import unittest2 as unittest
 
 
+@implementer(IVocabularyFactory)
 class TestVocabulary(object):
-    implements(IVocabularyFactory)
 
     def __call__(self, context):
         return SimpleVocabulary([