diff --git a/tangostationcontrol/tangostationcontrol/rpc/server.py b/tangostationcontrol/tangostationcontrol/rpc/server.py
index 8d22deec7bb993b2712426074b40383f1c723515..4130b21e55f365b0369458c12c78dc3b7fb19d1b 100644
--- a/tangostationcontrol/tangostationcontrol/rpc/server.py
+++ b/tangostationcontrol/tangostationcontrol/rpc/server.py
@@ -78,11 +78,13 @@ def _create_parser():
     parser.add_argument(
         "--port",
         default=50051,
+        type=int,
         help="HTTP port to listen on.",
     )
     parser.add_argument(
         "--metrics-port",
         default=8001,
+        type=int,
         help="Prometheus metrics HTTP port.",
     )
     parser.add_argument(