Sera from 124 cattle herds were tested, and antibodies to Crimean-Congo haemorrhagic fever (CCHF) were found in 93 herds. The prevalence of antibodies was high in the interior of the country, in excess of 90% in some herds, but was less than 4% in cattle along the coast from Cape Town to East London. Only 17 out of 1 109 (1.5%) human residents of 55 farms had antibodies to CCHF, while none of 164 veterinary research workers or 98 veterinarians engaged in farm animal practice had them. Specimens from 130 suspected cases of viral haemorrhagic fever were examined and CCHF was diagnosed only in the patient previously reported as the first case of the disease to be recognized in this country. A further 2 cases of CCHF were diagnosed by examining 318 specimens from patients with nonfatal febrile illness. Both patients had contact with livestock. Increasing awareness of the disease will probably lead to an increase in the number of cases diagnosed, but there are no grounds for concluding that the disease is on the increase.