OBJECTIVES: The aim of the present study is to evaluate the long term effects of estrogen-progestogen therapy (EPT) on uterine myomas volume in postmenopausal women. METHODS: We performed a retrospective analysis on postmenopausal women with asymptomatic uterine myoma during the period between April, 2008 and September, 2012. Postmenopause was defined as amenorrhea for longer than a year or serum follicle stimulating hormone levels higher than 40 IU/L. The volume of the myoma was assessed by transvaginal ultrasonography for every 6 months after administration of EPT. RESULTS: Thirty-eight women were included in the study, with 32 in the EPT group and 6 in the control group. Overall, uterine myoma volume (mean +/- standard deviation, cm3) in the EPT group was 19.5 +/- 24.6 at baseline, and those at 6 and 12 months were 24.7 +/- 35.1 and 28.5 +/- 56.4, respectively. Myoma volume did not change significantly with EPT, and these changes were not significantly different from the control group. Myoma volume changes were not significantly different in the subgroups according to the route of estrogen administrations and the method of progestogen administrations. Clinically significant volume increases during one year of EPT was noted in 28.1% (9/32), however, only one showed transient increases. CONCLUSION: Our results suggest that treating postmenopausal woman with EPT on a long-term basis does not increase the volume of uterine myomas.