Objective: To evaluate the efficacy of levonorgestrel intrauterine systems (LNG-IUS) in obese women with AUB on anticoagulant therapy. Design: Prospective observational case series (Canadian Task Force Classification II-3). Setting: University affiliated teaching hospital. Patients: Premenopausal women on Warfarin therapy. Interventions: From January 2002 through January 2007, 10 women were identified from the senior author's clinical practice (G.A.V.). After clinical assessment, including Papanicolaou smear, endometrial biopsy, and pelvic sonography, the LNG-IUS was placed to treat their AUB. Measurements and Main Results: The median and range of age, parity, and body mass index were 45 years (34-49), 1 (0-4), and 38 kg/m(2) (26-52), respectively. All women were receiving warfarin therapy (4-12.5 mg/d) for previous venous thromboembolism. Some patients had additional comorbid conditions and were at high risk for traditional medical or surgical therapies. After placement of the LNG-IUS all women reported menstrual reduction at 3 and 6 months. By 12 months, 1 woman with tar-e fibroids expelled the LNG-IUS and was treated with transfemoral uterine artery embolization. Two women had amenorrhea, and 7 had hypomenorrhea. At 2 to 5 years, 1 woman expelled the LNG-IUS and hysterectomy indicated extensive adenomyosis in a 195-g uterus, and 1 woman had hysteroscopic endometrial ablation, 4 were menopausal, 2 had amenorrhea, 3 and 1 had hypomenorrhea. In the 5 women with uterine fibroids measuring 4.2 to 147 cm(3), the fibroids were reduced in volume by approximately 75% in 2, were no longer detectable in 1, were subsequently shown to be adenomyoma in 1, and required uternie artery embolization in 1. Conclusion: In property assessed and selected obese. premenopausal women with AUB receiving warfarin therapy and at high risk for traditional therapies, the LNG-IUS was an effective treatment in 70% of patients. Journal of Minimally Invasive Gynecology (2009) 16, 480-484 (C) 2009 AAGL. All rights reserved.