Pneumoperitoneum is usually the result of a perforated gastrointestinal (GI) tract associated with peritonitis. However, on rare occasions, spontaneous pneumoperitoneum not associated with a perforated GI tract has been described in the literature. A ruptured liver abscess is one of these occasions, and herein a case that resulted in pneumoperitoneum is reported. A 61-year-old woman was referred to the ER with acute onset of abdominal pain. The patient had been diagnosed as having diabetes mellitus and hypertension. The abdominal examination was not remarkable for tenderness, but her vital signs were unstable. Laboratory investigations revealed a WBC count of 4, 000/mm3, Na+ of 129 mEq/L, and K+ of 3.2 mEq/L. A plain radiography disclosed a minute amount of free air in the left subphrenic space, and a computed tomography (CT) scan visualized a low-density cystic mass suspected to be a gas forming pyogenic liver abscess. A laparoscopic exploration was performed for diagnosis and peritoneal drainage. Under the laparoscopy, a ruptured liver abscess and large amount purulent plaque were observed scattered in the entire peritoneal cavity. Evacuation of the abscess, cholecystectomy, liver biopsies, and peritoneal lavage were carried out after conversion to an open laparotomy. An abscess culture was obtained from the liver, with Klebsiella pneumoniae revealed as the pathogen. The administration of appropriate antibiotics followed the surgery, and she recovered without complications. A ruptured pyogenic liver abscess is an extremely rare and threatening condition despite the advances in diagnostic technology and new strategies for their treatment. However, the appropriate surgical management, followed by effective antibiotic therapy, will recover the patient without serious complications.