An aetiological survey of 499 deaf Black children in 3 schools in Southern Africa is reported. Specific genetic syndromes were identified in 21 children, of whom 13 had the Waardenburg syndrome. Inherited deafness without associated defects was diagnosed in further 32 children, and an indentifiable acquired cause was evident in 108 children (22%). No cause could be found in the remaining 338 children (68%), of whom 71 had various nonspecific congenital anomalies.