diff --git a/Lib/urllib.py b/Lib/urllib.py
index d241ad4..94ddbb5 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -748,6 +748,7 @@
 	"""
 	proxies = {}
 	for name, value in os.environ.items():
+		name = string.lower(name)
 		if value and name[-6:] == '_proxy':
 			proxies[name[:-6]] = value
 	return proxies