The feeding ecology of lions (Panthera leo, Linnaeus 1758) was investigated in and around Waza National Park, northern Cameroon. Diet was determined using global positioning system (GPS) data of lion kill sites (clusters of GPS location points) collected using radio collars. Lions consumed 14 different prey species, with five species that were either medium (50–200 kg) or large (>200 kg) in size forming the bulk of kills. The western kob (Kobus kob kob) was the most common (23.5%) wild prey of lions, but worryingly livestock (predominantly cattle) constituted as much as 21.6% of the diet. This creates a conservation problem resulting in lions being killed in retaliation. However, this conflict is strongly exacerbated by herders driving their cattle into the park for forage and water. Wild prey was also consumed outside the park (6.7%), suggesting excursions beyond the park boundary. Lions showed a preference for wild prey over livestock when relative abundances were considered. Management efforts to reduce livestock intrusion into the park and to reverse the declining trends of wild prey populations would significantly reduce predation of livestock and prevent persecution of lions in this park, but conflict mitigation measures outside the park are also urgently needed.