diff --git a/scrapy/spidermanager.py b/scrapy/spidermanager.py
index a398e553b..25f984aa0 100644
--- a/scrapy/spidermanager.py
+++ b/scrapy/spidermanager.py
@@ -33,7 +33,10 @@ class SpiderManager(object):
         return cls(settings.getlist('SPIDER_MODULES'))
 
     def create(self, spider_name, **spider_kwargs):
-        return self._spiders[spider_name](**spider_kwargs)
+        try:
+            return self._spiders[spider_name](**spider_kwargs)
+        except KeyError:
+            raise KeyError("Spider not found: %s" % spider_name)
 
     def find_by_request(self, request):
         return [name for name, cls in self._spiders.iteritems()