OBJECTIVE To compare the efficacy and safety of the levonorgestrel-releasing intrauterine device (LNG-IUD) with dydrogesterone applied for the same duration in patients having endometrial hyperplasia (EH) without atypia. METHODS One hundred thirty eight women aged between 30 and 50 years with abnormal uterine bleeding and diagnosed as EH by transvaginal ultrasound were randomized to receive either LNG-IUD or dydrogesterone for 6 months. Primary outcome measures were regression of hyperplasia after 6 months of therapy. Secondary outcome measures were occurrence of side effects during treatment or recurrence of hyperplasia during follow-up period. RESULTS After 6 months of treatment, regression of EH occurs in 96% of women in the levonorgestrel-releasing intrauterine system (LNG-IUS) group versus 80% of women in the oral group (P < .001). Adverse effects were relatively common with minimal differences between the 2 groups. Intermenstrual vaginal spotting and amenorrhea were more common in the LNG-IUD group (P value .01 and .0001). Patient satisfaction was significantly higher in the LNG-IUS group (P value .0001). Hysterectomy rates were lower in the LNG-IUS group than in the oral group (P = .001). Recurrence rate was 0% in the LNG-IUD group compared to 12.5% in the oral group. CONCLUSIONS In management of EH without atypia, LNG-IUS achieves a higher regression and a lower hysterectomy rate than oral progesterone and could be used as a first-line therapy.