The posterior interosseous nerves of 58 cadaver forearms of black South Africans were dissected to study their order of branching. In 43 specimens (74%), the most common order of branching was: extensor carpi radialis brevis; supinator; extensor digitorum; extensor carpi ulnaris; extensor digiti minimi; abductor pollicis longus; extensor pollicis brevis; extensor pollicis longus and extensor indicis. In 15 specimens (26%) different variations of the nerve were observed, some of which are reported for the first time. The knowledge of these variations could be useful during operations in the vicinity of the nerve, and when repairing a nerve injury or forecasting the location of a compressive lesion.