diff --git a/osc/connection.py b/osc/connection.py
index 3e9f9c80..32216709 100644
--- a/osc/connection.py
+++ b/osc/connection.py
@@ -8,6 +8,7 @@ import ssl
 import sys
 import tempfile
 import time
+import warnings
 
 import http.client
 import http.cookiejar
@@ -25,6 +26,10 @@ from . import oscssl
 from .util.helper import decode_it
 
 
+# print only the first occurrence of matching warnings, regardless of location
+warnings.filterwarnings("once", category=urllib3.exceptions.InsecureRequestWarning)
+
+
 class MockRequest:
     """
     Mock a request object for `cookiejar.extract_cookies()`