Objective: To evaluate the efficacy of the levonorgestrel-releasing intrauterine system (LNG-IUS) in the treatment of leiomyoma related menorrhagia and to assess the effect of LNG-IUS on uterine, leiomyoma, and ovarian volume. Materials and Methods: In this prospective before and after study, LNG-IUS was inserted in 38 women with myoma-related menorrhagia. The patients were evaluated for serum levels of hemoglobin, hematocrit and uterine, leiomyoma, and ovarian volume at the time of insertion and at six months. Results: Significant reduction in the Pictorial Blood Loss Assessment Chart (PBAC) score and increases in serum hemoglobin levels and in amenorrhea was observed within three months. However, there was no statistically significant reduction in the myoma and uterine volume. Ovarian volume, also, did not changed significantly. Conclusion: The use of LNG-IUS is effective in reducing menorrhagia associated with leiomyomas with improvement in hemoglobin levels and may be a simple and effective alternative to surgical treatment of leiomyoma-related abnormal uterine bleeding (AUB-L) without significant influence on the volume of leiomyoma and ovarian and uterine volume.