diff --git a/letsencrypt/client/storage.py b/letsencrypt/client/storage.py
index 218b0e6a9..6f1f96199 100644
--- a/letsencrypt/client/storage.py
+++ b/letsencrypt/client/storage.py
@@ -35,29 +35,19 @@ class RenewableCert(object):  # pylint: disable=too-many-instance-attributes
     associated renewal configuration file."""
 
     def __init__(self, configfile, defaults=DEFAULTS):
-        if isinstance(configfile, str):
-            if not os.path.exists(configfile):
-                raise ValueError(
-                    "renewal config file {0} doesn't exist".format(configfile))
-            if not configfile.endswith(".conf"):
+        if isinstance(configfile, configobj.ConfigObj):
+            if not os.path.basename(configfile.filename).endswith(".conf"):
                 raise ValueError("renewal config file name must end in .conf")
-            self.lineagename = os.path.basename(configfile)[:-5]
-            self.configfilename = os.path.basename(configfile)
-        elif isinstance(configfile, configobj.ConfigObj):
             self.lineagename = os.path.basename(configfile.filename)[:-5]
-            self.configfilename = os.path.basename(configfile.filename)
-            if not self.configfilename.endswith(".conf"):
-                raise ValueError("renewal config file name must end in .conf")
         else:
-            raise TypeError("RenewableCert config must be file path "
-                            "or ConfigObj object")
+            raise TypeError("RenewableCert config must be ConfigObj object")
 
         # self.configuration should be used to read parameters that
         # may have been chosen based on default values from the
         # systemwide renewal configuration; self.configfile should be
         # used to make and save changes.
+        self.configfile = configfile
         self.configuration = copy.deepcopy(defaults)
-        self.configfile = configobj.ConfigObj(configfile)
         self.configuration.merge(self.configfile)
 
         if not all(self.configuration.has_key(x) for x in ALL_FOUR):
diff --git a/letsencrypt/client/tests/renewer_test.py b/letsencrypt/client/tests/renewer_test.py
index c08c7dc74..43854c281 100644
--- a/letsencrypt/client/tests/renewer_test.py
+++ b/letsencrypt/client/tests/renewer_test.py
@@ -73,14 +73,6 @@ class RenewableCertTests(unittest.TestCase):
         config["fullchain"] = "/tmp/fullchain.pem"
         config.filename = "/tmp/sillyfile"
         self.assertRaises(ValueError, storage.RenewableCert, config, defaults)
-        self.assertRaises(ValueError, storage.RenewableCert, "/tmp", defaults)
-
-    def test_renewal_config_filename_exists(self):
-        """Test that the RenewableCert constructor will complain if
-        the renewal configuration file doesn't exist."""
-        from letsencrypt.client import storage
-        defaults = configobj.ConfigObj()
-        self.assertRaises(ValueError, storage.RenewableCert, "XXXXX", defaults)
 
     def test_consistent(self): # pylint: disable=too-many-statements
         oldcert = self.test_rc.cert