In brachial plexus injuries, though nerve transfers and root grafts have improved the results for shoulder and elbow reconstruction, wrist extension has received little attention. We operated on three young patients with C5–C8 root injuries of the left brachial plexus, each operated upon within 6 months of trauma. For wrist extension reconstruction, we transferred a proximal branch of the flexor digitorum superficialis to the motor branch of the extensor carpi radialis brevis. Twenty-four months after surgery, all patients recovered some degree of active wrist motion, from full flexion to near neutral. Independent control of finger flexion and wrist extension was not observed. In C5–C8 root injuries of the brachial plexus, transfer of a flexor digitorum superficialis motor branch to the extensor carpi radialis brevis produces limited recovery. © 2012 Wiley Periodicals, Inc. Microsurgery, 2013.