Rupture of a flexor tendon in the nonrheumatoid population is rare. Localizing the level of the tendon rupture can be a difficult task. We describe an individual who presented with the sudden inability to flex the index finger of the hand, which had been subjected to a severe electrical injury. Physical exam demonstrated lack of index finger flexion at the distal joint. The patient denied any pain or history of recent trauma. Preoperative magnetic resonance imaging (MRI) successfully located the proximal and distal ends of the ruptured flexor digitorum profundus tendon in the forearm. MRI allows for accurate preoperative assessment of tendon position and degree of retraction, thereby facilitating surgical planning and approach. Accurate localization of tendon pathology preoperatively minimizes unnecessary dissection, shortens the operative procedure, and clarifies operative planning.Concannon MJ, Duffy FJ Jr, Palmer WE, May JW Jr. Late rupture of a flexor tendon after electrical injury: tendon localization using magnetic resonance imaging. A case report. Ann Plast Surg 1996;36:84-87