In this study, Staphylococcus aureus was isolated from a draught horse presented to Kassala Veterinary Research Laboratory (KVRL) for investigation and diagnosis. The affected animal was previously treated with Gentamycin and Tetracycline before submitted to this laboratory, but the animal was not cure. Thereafter, the animal was attended to the laboratory; it was suffering from inguinal abscess and some clinical signs. Clinical and laboratory examinations were carried out however, the animal was suddenly fallen and died immediately. Then post-mortem, bacteriological and histopathological examinations were done. S. aureus was isolated as pure culture from the lungs and peritoneum of the necropsied animal. This isolate showed highly sensitivity to Erythromycin and Clindamycin and it was resistant to Penicillin, Cloxacillin, Cefotaxime, Co-Trimoxazole, Cephalexin and Tetracycline. It was concluded from this study, the shock resulted from S. aureus was the causative agent of the death in this case.