A new case of isolated paralysis of the anterior interosseous nerve of a 24-year-old man is described. It is thought that this was caused by a fall on the left arm. This paralysis has a typical clinical picture with a characteristic disturbance of the pinch grip. The patient recovered spontaneously. A review of the findings previously reported in the literature is presented. J Orthop Sports Phy Ther 1984;6(3):178-180.