diff --git a/apns2/client.py b/apns2/client.py
index fd2a824..35fe9b9 100644
--- a/apns2/client.py
+++ b/apns2/client.py
@@ -24,11 +24,11 @@ logger = logging.getLogger(__name__)
 
 
 class APNsClient(object):
-    def __init__(self, cert_file, use_sandbox=False, use_alternative_port=False, proto=None, json_encoder=None):
+    def __init__(self, cert_file, use_sandbox=False, use_alternative_port=False, proto=None, json_encoder=None, password=None):
         server = 'api.development.push.apple.com' if use_sandbox else 'api.push.apple.com'
         port = 2197 if use_alternative_port else 443
         ssl_context = init_context()
-        ssl_context.load_cert_chain(cert_file)
+        ssl_context.load_cert_chain(cert_file, password=password)
         self.__connection = HTTP20Connection(server, port, ssl_context=ssl_context, force_proto=proto or 'h2')
         self.__json_encoder = json_encoder
         self.__max_concurrent_streams = None