BACKGROUND Abnormal uterine bleeding is defined as any alteration in the pattern or volume of menstrual blood flow, and it is preferably treated using hysterectomy, endometrial destruction or the levonorgestrel-releasing intrauterine system (Mirena(®) ). Recently, it has been demonstrated that studies of Mirena(®) were generally small and consequently imprecise. OBJECTIVE Our study was aimed at assessing the effects of a slow-release levonorgestrel (20 μg/day) intrauterine device in fertile and postmenopausal women experiencing abnormal uterine bleeding that did not respond to traditional medical management. METHODS A total of 40 women, of whom 24 were of reproductive capacity and 16 were postmenopausal, were enrolled in the trial. Removal of the intrauterine device was required for only 2 of the 24 fertile women and for only 3 of the 16 postmenopausal women. After 6 and 12 months of treatment, the remaining women were clinically evaluated and underwent ultrasound and hysteroscopy using biopsy specimens as a control. The EuroQol Group EQ-5D questionnaire was used for evaluation of quality of life. RESULTS The device showed good tolerability and efficacy. It resulted in a reduction in the endometrial mucosal thickness with a regression of bleeding and collateral effects, which were more evident after 12 months of treatment. A positive effect of the device on the woman's quality of life was demonstrated. CONCLUSIONS The slow-release levonorgestrel intrauterine device may be a valid therapeutic tool for treating basic symptomatology and increasing quality of life in women with abnormal uterine bleeding.