OBJECTIVE: To evaluate the efficacy of a Levonorgestrel-releasing Intrauterine System (LNG-IUS) in controlling menorrhagia in comparison with endometrial thermal rollerball ablation.DESIGN: Seventy-nine consecutive patients with menorrhagia underwent either LNG-IUS insertion (n=42) or hysteroscopical endometrial thermal rollerball ablation (n=37) in a prospective, observational, comparative study. Women reported duration of uterine bleeding in days prior to, and six and 12 months after each intervention. Prior to each intervention, endometrial, cervical or other pathological conditions of the genital tract were excluded. GnRH analogues for endometrial suppression were given for ten weeks before endometrial ablation but not prior to LNG-IUS insertion.RESULTS: There were no differences in duration of uterine bleeding before each intervention in the two groups. The duration of uterine bleeding was lower in the LNG-IUS group as compared with endometrial ablation at six (p<0.001) and 12 months (p<0.001) after each intervention. Furthermore, the effect on reduction of bleeding was stronger in the LNG-IUS group as compared with the endometrial ablation group at six (p<0.001) and 12 months (p<0.001).CONCLUSIONS: The LNG-IUS was more efficacious than endometrial thermal ablation in reducing duration of uterine bleeding at six and 12 months post-intervention.