OBJECTIVE : The impact of estradiol-based hormone therapy (HT) on the incidence of stress urinary incontinence (SUI) is unknown. Therefore, we compared the use of such HT regimens and tibolone in women with and without SUI. METHODS : The women with a history of SUI operation (N = 15,002) were identified from the Finnish National Hospital Discharge Register, and the control women without such an operation (N = 44,389) from the Finnish Central Population Register. The use of HT was traced from the National Drug Reimbursement Register, and the odd ratios (ORs) with 95% confidence intervals (95% CIs) for SUI were calculated by using the conditional logistic regression analysis. RESULTS : The cases had used any HT more often than the controls. The use of systemic estradiol-only or estradiol-progestin therapy was accompanied by an increased SUI risk (OR 3.8, 95% CI: 3.6-4.0 and OR 2.7, 95% CI: 2.6-2.9 respectively). The use of estradiol with noretisterone acetate showed a higher risk of increase than that with medroxyprogesterone acetate. Age over 55 years at the initiation of systemic HT was accompanied by a higher SUI risk increase than that under 55 years of age. The use of tibolone, an estradiol + levonorgestrel-releasing intrauterine device, or vaginal estradiol also increased the risk. CONCLUSIONS : The use of HT regimens may predispose to the de novo development or worsening of pre-existing SUI. Thus, caution is needed when these regimens are prescribed to women with mild stress-related urine leakage or with established SUI risk factors.