This chapter discusses the case of a 66-year-old woman who presented with a 2-week history of left-sided abdominal pain. On examination, she was mildly pyrexial with a heart rate of 76 beats/min. Abdominal examination revealed tenderness in the left iliac fossa. Urinalysis was normal. A CT scan showed evidence of free intraperitoneal gas, sigmoid diverticulitis, and an 8 cm pelvic abscess containing gas. She underwent pelvic abscess drainage and thorough peritoneal lavage with 8 liters of saline, and a nonsuction drain was left in the pelvis. Postoperatively, she remained on broad-spectrum intravenous antibiotics. Three days later, feculent fluid was seen in the pelvic drain. On examination, she was tender with guarding in the left iliac fossa. Perforated diverticulitis with generalized peritonitis usually requires sigmoid resection and Hartmann's procedure. Laparoscopic peritoneal lavage is becoming increasingly popular in the management of perforated diverticulitis which is not responding to conservative management.