Peritonitis is a significant complication of peritoneal dialysis (PD) and the most common cause of technique failure. Panton-Valentine leukocidin (PVL), a cytotoxin produced by certain strains of Staphylococcus aureus (SA), causes destruction of neutrophils, and is associated with severe invasive infections. We present a 2.5-year-old girl on PD, who presented suddenly with an unusually fulminant and protracted course of peritonitis. Only a few hours after the onset of clinical signs, septic shock developed. PVL-positive methicillin-sensitive SA (MSSA) was grown and initial empiric antibiotic treatment changed to flucloxacillin and rifampicin in order to minimize toxin production. In spite of adequate antibiotic treatment and PD-catheter removal, recovery was slow. No PD-related peritonitis in children associated with PVL-producing strains have been reported so far and no specific recommendation exists for treatment. We speculate that PVL contributed to the severity and outcome of peritonitis in our patient.