diff --git a/Lib/http/client.py b/Lib/http/client.py
index a6ab135b2c3879b..f54172fd0deeaed 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -593,8 +593,8 @@ def _read_chunked(self, amt=None):
                     amt -= chunk_left
                 self.chunk_left = 0
             return b''.join(value)
-        except IncompleteRead:
-            raise IncompleteRead(b''.join(value))
+        except IncompleteRead as exc:
+            raise IncompleteRead(b''.join(value)) from exc
 
     def _readinto_chunked(self, b):
         assert self.chunked != _UNKNOWN