Spirocerca lupi is a parasitic nematode that causes spirocercosis predominantly in domestic dogs. Spirocerca lupi nematode samples were collected from four regions around South Africa and analyzed to compare the genetic diversity among the regions. A total of 56 S. lupi nematodes were obtained by necropsy from domestic dogs and wild black-backed jackals (Canis mesomelas). Sixteen different haplotypes of cox1 were identified some of which are shared between regions as well as with black-backed jackal. The genetic similarity between S. lupi in domestic dogs and black-backed jackals indicates transmission between these canid species and may have potential conservation implications.