The conflict between predators and livestock farmers is a threat to carnivore conservation. Livestock guarding dogs are promoted as a non-lethal, environmentally friendly method to mitigate this conflict. As part of a farmer–carnivore conflict mitigation programme, the Cheetah Conservation Fund breeds Anatolian shepherd (also known as Kangal) dogs to protect livestock from predators. During 2009–2010 we interviewed 53 commercial and 20 subsistence Namibian farmers that are using 83 such dogs. Fewer commercial and subsistence farmers reported livestock losses to predators during the most recent year of guarding-dog use compared to the year before dogs were introduced. All subsistence farmers, but not all commercial farmers, ceased killing predators during the most recent year of guarding-dog use. All farmers ceased killing cheetah Acinonyx jubatus and leopard Panthera pardus during this year, and one dog killed a single cheetah. Conversely, dogs and farmers killed more black-backed jackals Canis mesomelas between them in the survey year than the farmers reported killing in the year before acquiring dogs. Two of the dogs reportedly killed non-target carnivore species, and 15 killed prey species. Thus our results challenge the categorization of livestock guarding dogs as a non-lethal conflict mitigation method. We suggest that the conservation status and body size of wild carnivores relative to the size of the guarding dogs be considered before introducing dogs to protect livestock. Additionally, corrective training for dogs that chase or kill non-target species should be implemented, especially where farmers value these species or where non-target species are threatened.