Septic arthritis of the hip joint in two children, originally thought to be cases of acute abdomen is presented. In one case, the discovery of extra-peritoneal purulent fluid at surgery, obviated the need for laparotomy and in the other, the true nature of the disease became apparent one week after laparotomy. These cases illustrate the maxim that any painful movement of the hip joint with associated unexplained fever should raise suspicion of septic arthritis. The close relationship of the hip joint to the pelvis sometimes confuses hip diseases with pelvic pathologies. Key Words: Septic arthritis, acute abdomen, pathological dislocation Nigerian Journal of Paediatrics 2003; 30: 67-70.