diff --git a/scrapy/trunk/scrapy/contrib/spidermiddleware/duplicatesfilter.py b/scrapy/trunk/scrapy/contrib/spidermiddleware/duplicatesfilter.py
index 369cbf89c..1760006cf 100644
--- a/scrapy/trunk/scrapy/contrib/spidermiddleware/duplicatesfilter.py
+++ b/scrapy/trunk/scrapy/contrib/spidermiddleware/duplicatesfilter.py
@@ -39,8 +39,7 @@ class DuplicatesFilterMiddleware(object):
         dispatcher.connect(self.filter.close, signals.domain_closed)
 
     def process_spider_input(self, response, spider):
-        if not self.filter.add(spider.domain_name, response.request):
-            raise IgnoreRequest("Skipped (already processed): %s" % response.request)
+        self.filter.add(spider.domain_name, response.request)
 
     def process_spider_output(self, response, result, spider):
         domain = spider.domain_name
diff --git a/scrapy/trunk/scrapy/tests/test_spidermiddleware_duplicatesfilter.py b/scrapy/trunk/scrapy/tests/test_spidermiddleware_duplicatesfilter.py
index 11325437b..606ff1687 100644
--- a/scrapy/trunk/scrapy/tests/test_spidermiddleware_duplicatesfilter.py
+++ b/scrapy/trunk/scrapy/tests/test_spidermiddleware_duplicatesfilter.py
@@ -32,10 +32,6 @@ class DuplicatesFilterMiddlewareTest(unittest.TestCase):
         assert r2 in filtered
         assert r3 not in filtered
 
-        response = Response('http://scrapytest.org/')
-        response.request = Request('http://scrapytest.org/')
-        self.assertRaises(IgnoreRequest, mw.process_spider_input, response, self.spider)
-
         mw.filter.close('scrapytest.org')