Objectives: This study compared the efficacy of the levonorgestrel-releasing intrauterine device (LNG-IUD) to oral medroxyprogesterone acetate (MPA) applied for the same length of time for the management of endometrial hyperplasia without atypia. Study Design: This was single-center, open, randomized, and clinical trial. One hundred four patients aged between 30-50 years and diagnosed with endometrial hyperplasia without atypia by endometrial biopsy, were randomized to receive LNG-IUD or MPA. Both groups were further divided into two groups as three-month and six-month treatment subgroups. The primary objective was to compare the complete regression rates of hyperplasia, and the secondary objective was to determine the minimum duration of time required for the achievement of regression. Results: At two-year follow-up, the success rates of LNG-IUD treatment and oral MPA for three months therapy were 84% and 50%, respectively. While the regression rate was 100% in the six-month LNG-IUD group, it was 64% in the oral MPA group. LNG-IUD appeared to have a significantly higher success rate (p = 0.0001). Conclusion: It is believed that by this study LNG-IUD applications may be a reliable preference for younger patients who wish to preserve their uterus and especially for non-atypical cases, and if the patient demands fertility, even a six-month application will provide effective treatment.