diff --git a/Lib/chunk.py b/Lib/chunk.py
index bda965fd6f0..a8fbc1051f3 100644
--- a/Lib/chunk.py
+++ b/Lib/chunk.py
@@ -62,7 +62,7 @@ class Chunk:
         if len(self.chunkname) < 4:
             raise EOFError
         try:
-            self.chunksize = struct.unpack(strflag+'l', file.read(4))[0]
+            self.chunksize = struct.unpack(strflag+'L', file.read(4))[0]
         except struct.error:
             raise EOFError
         if inclheader:
diff --git a/Misc/NEWS b/Misc/NEWS
index 073ef6ce8c0..619549d722c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -363,6 +363,9 @@ Extension Modules
 Library
 -------
 
+- Patch #1373643: The chunk module can now read chunks larger than
+  two gigabytes.
+
 - Patch #1417555: SimpleHTTPServer now returns Last-Modified headers.
 
 - Bug #1430298: It is now possible to send a mail with an empty