Leptospirosis is a disease caused by pathogenic spirochetes of genus Leptospira. It is considered the most common zoonosis in the world. Acute pancreatitis is a rare complication of leptospirosis (25%). We present the case of a 34-year-old male patient with severe leptospirosis complicated with acute renal failure. After 9 days from the onset of the disease, the patient developed acute necrotizing pancreatitis, infected from the very beginning, associated with multiple organ failure, septic shock and severe anemia. The diagnosis was clinically and biologically stated and confirmed by CT-scan. The patient underwent surgery for infected necrotizing acute pancreatitis of the head and neck of the pancreas, with left retroperitoneal expansion down to the left iliac fossa. We performed a necrosectomy with the evacuation of the tisular debris, multiple drainage of the peritoneal cavity, followed by an open abdomen with synthetic mesh. The postoperative evolution was difficult but constantly progressive. Two reinterventions were necessary. The patient left the hospital in good condition after 75 days postoperatively.