A serious outbreak of rabies among kudus in South West Africa/Namibia has accounted for the deaths of an estimated 10,000 of them since 1977. The disease has spread at a rate of 40-60 km/yr, although its progress in an easterly direction was checked for > 2 yr by a game fence. Although the fence restricted the movements of big game such as kudus, it did not prevent movement of the known vectors of rabies such as dogs and jackals. The outbreak coincided with a few years of above average rainfall with a resultant improvement in vegetation and an increase in the population density of kudus and jackals. The incorporation of game, especially kudus, into the farming industry in South West Africa/Namibia and the greater awareness of farmers for the need of protection contributed to the population increase of kudus. A horizontal spread of the disease among kudus is suggested. Factors involved include their grooming habits, social behavior, the restricted spread of the disease through the game fence and the absence of a corresponding increase in the number of cases of rabies in other species. Mouth lesions caused by the browsing of thorn-bush may be a contributory factor.