Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis. With the review of the literature, we reported two cases of XPN with psoas muscle abscesses caused by Staphylococci aereus in one of the patient and Serratia mascerentes in the other. Both of the patients had renal calculus. We performed nephrectomy with psoas abscess drainage and started appropriate antibiotics, but one of the patients died of septic shock. Other patient is free of symptoms at the end of 5 years follow-up.