Although dislocation of the distal radioulnar joint is commonplace in association with fractures of the radial shaft, irreducible dislocation has previously been considered to be rare. In the only three previously reported cases the tendon of the extensor carpi ulnaris blocked reduction of the distal radioulnar joint in Galeazzi injuries. The cases presented in this report show that other tendons may be involved, and that the injury may occur even when the ulna is broken. It is likely that the injury described is more common than is realized and is usually overlooked.