The incidence and causes of mortality in a mixed ratite farm which produced ostriches and emus were recorded over four production seasons (1998 - 2001). The mean annual mortality rates for ostrich and emu chicks during the rearing phase were 29.1% and 21.6%, respectively. The mortality rate was 46.3% for the whole chick population during four production seasons. Notable causes of chick mortality were leg deformity, fading chick syndrome, Newcastle disease (NCD), suffocation and enteric infection. The crude mortality rate for ostrich and emu growers throughout the study period was 18.7% with an annual mean of 12.3%. Sand impaction, NCD and leg deformity were the main causes of mortality among this group of birds. Septicaemic pasteurellosis was the major cause of death among breeding ostriches, while wound infection and peritonitis assumed minor roles. Egg peritonitis, accidents and enteritis were the most important causes of death among emu breeders.