Spontaneous perforation of pyometra resulting in generalized diffuse peritonitis is extremely uncommon. Here in, we report the case of a 63-year-old woman who presented to emergency department with a 2-day history of severe diffuse abdominal pain, high-grade fever, nausea, and vomiting. Acute abdomen series was done, and upright plain chest radiograph showed free air under diaphragm. Anoncontrast-enhanced computed tomography scan showed a significantly distended fluid-filled uterus measuring 10 × 7.8 × 10 cm, in addition to a single focus of perforation involving the uterine fundus and associated with presence of free air within the nondependant area. No evidence of ascites or pelvi-abdominal lymphadenopathy was identified. A preoperative diagnosis of generalized peritonitis secondary to spontaneous perforation of uterus was established. Subsequently, patient underwent urgent exploratory laparotomy which revealed pus-filled uterus with perforated fundus. Diagnosis of generalized peritonitis secondary to spontaneous perforation of pyometra was established. Consequently, patient underwent total abdominal hysterectomy with bilateral salpingooophorectomy, as well as thorough drainage and irrigation of pelvi-abdominal cavity. Postoperatively, patient was admitted to intensive care unit. Histopathological examination of uterus was negative for malignancy, and surgical culture grew Streptococcus constellatus. Patient had an uneventful recovery. Moreover, a brief literature review on pyometra is presented. [ABSTRACT FROM AUTHOR]