We report a patient with bidirectional dislocation of the distal radioulnar joint after malunited distal radius fracture, in which the ulnar head dislocated dorsally during forearm pronation and palmarly during supination without manual compression of the ulnar head. The patient had chronic ulnar wrist pain and experienced a painful clunk during forearm rotation. The distal radioulnar joint ballottement test was positive in both the dorsal and palmar directions. Her distal radius was malunited with a 20 dorsal angulation and 18 pronation deformity. A corrective osteotomy of the radius with open repair of the triangular fibrocartilage complex foveal avulsion yielded success. At the 7-year follow-up, there was almost a normal range of wrist and forearm motion, 83% grip strength, no arthritis, and a stable distal radioulnar joint. Copyright (C) 2016 by the American Society for Surgery of the Hand. All rights reserved.