diff -r 7eb7637e34bf -r 1bc01490178a hgext/lfs/blobstore.py
--- a/hgext/lfs/blobstore.py	Mon Jan 28 03:20:31 2019 -0500
+++ b/hgext/lfs/blobstore.py	Mon Jan 28 21:35:06 2019 -0500
@@ -428,6 +428,7 @@
             request.data = filewithprogress(localstore.open(oid), None)
             request.get_method = lambda: r'PUT'
             request.add_header(r'Content-Type', r'application/octet-stream')
+            request.add_header(r'Content-Length', len(request.data))
 
         for k, v in headers:
             request.add_header(pycompat.strurl(k), pycompat.strurl(v))