Uterine fibroids are associated with heavy menstrual bleeding, abdominal discomfort, subfertility and a reduced quality of life. The present study reported a case series of life-threatening anemia with hemoglobin levels <2.0 g/dl caused by uterine fibroids and genital bleeding. Case 1 was of a 34-year-old woman who was transported to the emergency department of the Department of Obstetrics and Gynecology, Faculty of Medicine, Oita University because of a decline in consciousness level. She had been experiencing excessive and prolonged menstruation for many years but had not sought medical help. A 5-cm uterine submucosal leiomyoma was detected and the patient underwent hysteroscopic myomectomy. Case 2 was of a 36-year-old woman with a history of blood transfusions owing to severe anemia who was presented with progressive dyspnea. Although it was repeatedly explained her that her condition was life threatening, she refused to be hospitalized. Her hemoglobin level was 1.7 g/dl. Multiple uterine fibroids and adenomyosis were detected and total hysterectomy was performed. Case 3 was of a 49-yearold woman who was transported to the emergency department of the Department of Obstetrics and Gynecology, Faculty of Medicine, Oita University due to abdominal pain and severe anemia. Blood testing revealed a hemoglobin level of 1.9 g/dl. Multiple uterine fibroids with a maximum diameter of 8.5 cm were detected. However, the patient insisted on discharge because of lack of disease awareness. Total hysterectomy was performed. The present study is the largest case series showing a detailed clinical course of patients with life-threatening anemia with hemoglobin levels <2.0 g/dl. Additionally, Case 1 of the present series exhibited the lowest hemoglobin level (1.1 g/dl) reported to date. The present cases and a review of the literature suggested that the most important risk factors of life-threatening anemia are the patient's mental, social and personal factors, rather than the organic and functional abnormalities of the uterus.