BuDOMINAL C O M P L I C A T I O N S of leukemia in childhood are relatively ncommon. Kuffer et al? encountered intraabdominal complications in 13 of 259 children with leukemia (5~). These complications included intraabdominal abscesses in nine patients (appendiceal, liver, and renal abscesses), intestinal obstruction in two patients, pancreatitis in one, and gallstones in one. Prolla and Kirsner, 2 in a review of autopsy findings in 148 cases of leukemia in children and adults, found necrotic lesions in 8 of 75 evaluable patients (11%) and bacterial peritonitis in 10 of the 148 cases (7%). The bacterial peritonitis was due to ruptured appendicitis in three cases, rupture of the large intestine in three cases, rupture of liver abscesses in two cases, and perforation of agranulocytic abscesses of the terminal ileum in two cases. Prolla and Kirsner stated that these complications tended to be fatal because of the poor condition of the patients. When possible, it is desirable to avoid major or extensive abdominal surgery in the leukemic child. This report is of an unusual instance in which a formal laparotomy was avoided in a leukemic child with roentgen evidence of free air in the peritoneal cavity at a time when the findings on physical examination suggested spontaneous closure of the perforation and the absence of ongoing peritonitis. The patient, a 5-yr-old Oriental female with a 33-mo history of acute lymphocytic leukemia with treatment, was admitted to the UCLA-Harbor General Hospital with a 3-day complaint of abdominal pain, fever, and anorexia. The symptoms had appeared to diminish in severity 1 day prior to admission to the hospital. Intraabdominal testes had been removed in the first week of life because of male pseudohermaphrodit ism. Karotype analysis at birth and at the time of the onset of leukemia had revealed 46 chromosomes and an XY karotype. She had experienced six complete or partial relapses of her leukemic state and had been given one or more of the following chemotherapeutic agents: prednisone, methotrexate, vincristine, 6-mercaptopurine, cyclophosphamide, l-asparaginase, and cytosine arabinoside. Her antileukemia therapy for the sixth relapse had been started 4 wk prior to the onset of her abdominal symptoms and consisted of prednisone 10 mg three times daily and vincristine 1 mg i.v. once a week. On admission to the hospital, her white blood count was 6100 with 80% granulocytes, 18% lymphocytes, and 2% monocytes. A bone marrow aspiration