diff --git a/pgpasslib.py b/pgpasslib.py
index 3cfd221..ab5b82b 100644
--- a/pgpasslib.py
+++ b/pgpasslib.py
@@ -70,12 +70,15 @@ def getpass(host=DEFAULT_HOST, port=DEFAULT_PORT, dbname=DEFAULT_DBNAME,
     :raises: InvalidEntry
 
     """
+
     if not isinstance(port, int):
         port = int(port)
     for entry in _get_entries():
         if entry.match(host, port, dbname, user):
             return entry.password
-    return None
+
+    raise NoMatchingEntry("host=%s; port=%i; dbname=%s; user=%s"
+                          % (host, port, dbname, user))
 
 
 class PgPassException(Exception):
@@ -94,6 +97,14 @@ class FileNotFound(PgPassException):
     MESSAGE = 'No such file "{0}"'
 
 
+class NoMatchingEntry(PgPassException):
+    """Raised when the password file doesn't contain a match for the specified
+    connection parameters.
+
+    """
+    MESSAGE = 'No match for connection entry "{0}"'
+
+
 class InvalidEntry(PgPassException):
     """Raised when the password file can not be parsed properly due to errors
     in the entry format.
diff --git a/tests.py b/tests.py
index f4f68cd..5101fa6 100644
--- a/tests.py
+++ b/tests.py
@@ -242,11 +242,19 @@ def test_getpass_returns_expected_result(self):
 
 
 class GetPassNoMatchTest(unittest.TestCase):
-
-    def test_getpass_returns_expected_result(self):
+    def test_path_matches_expectation(self):
         with mock.patch('pgpasslib._read_file') as read_file:
             read_file.return_value = MOCK_CONTENT
-            self.assertIsNone(pgpasslib.getpass('fail', '5432', 'foo', 'bar'))
+            self.assertRaises(pgpasslib.NoMatchingEntry,
+                              lambda: pgpasslib.getpass('fail', '5432', 'foo',
+                                                        'bar'))
+
+
+class NoMatchingEntryStrFormatting(unittest.TestCase):
+    def test_str_matches_expectation(self):
+        msg = "host=fail; port=5432; dbname=foo; user=bar"
+        self.assertEqual(str(pgpasslib.NoMatchingEntry(msg)),
+                         'No match for connection entry "%s"' % msg)
 
 
 class FileNotFoundStrFormatting(unittest.TestCase):