This study aimed to evaluate the therapeutic yield of levonorgestrel-releasing intrauterine device (LNG-IUD) for management of tamoxifen induced menorrhagia in women who had mastectomy for treatment of breast cancer. This study included 34 patients who had breast cancer, underwent mastectomy, were maintained on tamoxifen post-operatively for at least 6 months, and had also newly developed menorrhagia throughout their follow-up period. All the patients underwent clinical examination for determination of duration and heaviness of menstrual blood loss (MBL), transvaginal ultrasonography (TVU) and endometrial biopsy for exclusion of abnormal pathology, estimation of blood iron indices and quality of life (QoL) scoring. Baseline endometrial biopsy detected simple endometrial hyperplasia (EH) in 4 patients and 30 patients had proliferative endometrium. Three patients were excluded and 31 patients completed the follow-up period without the need for shift to hysterectomy. Both mean duration and heaviness of MBL showed significant progressive decrease throughout the observation period as compared to baseline data. At the end of follow-up period, 5 women became amenorrheic, 2 women had moderate MBL and 24 women had mild MBL. Iron indices studies showed significant improvement at the end of follow-up as compared to baseline indices and total QoL scoring recorded at 6 and 12 months after enrollment were significantly higher as compared to baseline scores with significantly higher scores at 12 months. LNG-IUD could be considered as an appropriate therapeutic modality for tamoxifen-induced menorrhagia in patients who had mastectomy for breast cancer with significant reduction of duration and severity of MBL and improved QoL and iron indices.