diff --git a/koji/__init__.py b/koji/__init__.py
index 55e11ae6..95bd44ca 100644
--- a/koji/__init__.py
+++ b/koji/__init__.py
@@ -2321,6 +2321,7 @@ class ClientSession(object):
             if catcher:
                 warnings.simplefilter("ignore")
             r = self.rsession.post(handler, **callopts)
+            r.raise_for_status()
             try:
                 ret = self._read_xmlrpc_response(r)
             finally:
diff --git a/koji/compatrequests.py b/koji/compatrequests.py
index 2855da0f..7f6a14d3 100644
--- a/koji/compatrequests.py
+++ b/koji/compatrequests.py
@@ -121,6 +121,11 @@ class Response(object):
         self.session = session
         self.response = response
 
+    def raise_for_status(self):
+        if self.response.status >= 400:
+            raise httplib.HTTPException("HTTP %s: %s" % (self.response.status,
+                    self.response.reason))
+
     def iter_content(self, blocksize=8192):
         # should we check this in Session.post()?
         # should we even check this here?