PURPOSE: This study was conducted to evaluate the use of toremifene as an adjuvant hormonal therapy for estrogen recepter (ER) positive early breast cancer patients in terms of therapeutic efficacy and effect on endometrium as compared with tamoxifen. METHODS: Between January 2001 and December 2003, 451 patients with stage 0, I and II breast cancer, received adjuvant hormone therapy that consisted of either tamoxifen (N=387) or toremifene (N=64). The recurrence rate and survival rate were compared between two groups and the incidence of of endometrial event was evaluated in 273 of the patients. RESULTS: The median follow up period was 57 months and the median hormonal therapy period was 51 months. During the follow up period, there were 3 (2.0%) recurrence in the stage I tamoxifen group, 19 recurrences (8.7%) and 3 deaths (1.4%) in the stage II tamoxifen group (n=219), however there were no instances of recurrence or death in all of the toremifene group. In addition, endometrial cancer developed in 2 patients in the tamoxifen group, but in no patients in toremifene group during the follow up period. Further 21 of the patients who began treatment using tamoxifen changed to toremifene due to adverse side effects. The toremifene was well tolerated by 15 of the patients that changed treatment regimes. CONCLUSION: Toremifene was found to be as effective and safe as tamoxifen, when used as an adjuvant hormonal therapeutic agent in ER-positive early breast cancer, therefore toremifene may be a good option in place of tamoxifen for patients who are experiencing adverse effects as a result of tamoxifen treatment.