Hepatozoonosis was studied in hyaenas, lions, jackals, cheetahs and one leopard in the Kruger National Park and compared with the condition seen in dogs in the Republic of South Africa. Hepatozoon schizonts were found in the wild carnivores. The genesis of microschizonts was followed and is illustrated. The schizonts were sometimes very plentiful in the lung, myocardium and skeletal muscle, and were also encountered in the spleen, liver and lymph nodes. Gametocytes were present in leucocytes. The host response was usually very mild. sporogenous development in ticks was observed in Rhipicephalus simus females removed from an infected hyaena and R. sanguinelus adults fed on an infected jackal in the nymphal stage. Attempts to transmit Hepatozoon from a jackal to dogs by means of ticks gave inconclusive results.