A 61-year-old man, involved in an automobile accident, sustained a complete Achilles tendon rupture with an ipsilateral, closed slightly displaced medial malleolus ankle fracture. The tendon rupture was not diagnosed before operation but was recognized at the time of open reduction of the ankle. This rare combination of injuries was apparently secondary to hyperdorsiflexion of the foot. The tendon rupture would have been missed had surgical treatment not been required. Unrecognized tendon ruptures associated with closed ankle fractures may be a cause of residual ankle-foot weakness, pain, loss of motion, or a combination thereof.