Extensor pollicis longus tendon rupture is well known as a complication of fracture of the distal radius. There is a higher risk that the tendon of extensor pollicis longus will rupture in undisplaced distal radius fracture than in those which are displaced. We have experienced three cases of rupture of the extensor pollicis longus tendon after undisplaced distal radius fracture. Those were treated by tendon graft and tendon transfers. The results were satisfactory without complications. The patients with undisplaced distal radius fracture should be careful concerned about possibility of rupture of extensar pollicis tendon.