diff -r e745fe5c722c Lib/http/client.py
--- a/Lib/http/client.py	Tue Apr 19 04:05:59 2016 +0000
+++ b/Lib/http/client.py	Wed Apr 20 00:32:20 2016 -0400
@@ -321,8 +321,10 @@
         self.headers = self.msg = parse_headers(self.fp)
 
         if self.debuglevel > 0:
-            for hdr in self.headers:
-                print("header:", hdr, end=" ")
+            print("header:", end=" ")
+            for hdr, value in self.headers.items():
+                print(hdr + ":", value, end=" ")
+            print("")
 
         # are we using the chunked-style of transfer encoding?
         tr_enc = self.headers.get("transfer-encoding")