A 51-year-old morbidly obese, hypertensive, anemic, and amenorrheic female presented with anuria and respiratory symptoms. The patient had a distinctly massive abdomen with necrotic anterior abdominal wall, and laboratory findings revealed a leukocytosis, profound anemia, coagulopathy and renal failure. An abdominal sonogram showed a large, complex intra-abdominopelvic mass and ascites. At surgery, a massive, cystic left ovarian mass, 37 1 of ascitic/cyst fluid, and several peritoneal nodules were removed--a total of 64 kg of tumorous tissue. Histopathological evaluation of the mass revealed an endometrioma. We present this rare case of severe endometriosis in a morbidly obese patient who presented with an exceptionally large endometrioma (64 kg), multifactorial respiratory and renal failure, coagulopathy, and profound anemia.