Treatments for infertility in bulls are not described in homeopathic literature. A few treatments, such as changing the protein content of the diet, giving extra minerals, etc have been proposed. This case report describes homeopathic treatment for infertility in a prize bull. A Nelore bull, considered infertile for 3 years, was treated with homeopathic Pulsatilla nigricans 200 CH. Decreased total sperm defects, increased sperm motility and a very impressive increased number of doses of semen produced were observed. The bull relapsed after treatment was withdrawn, but again responded when it was resumed. Since only one animal was observed one cannot assume that the observed changes were due only to this treatment. Further studies may establish the real benefits of a homeopathic medicine in bull infertility.