The objective of the study was to examine the association of hormone therapy with incident urinary incontinence (UI) in postmenopausal women aged 37-54 years in the Nurses' Health Study II.Participants reported use of hormone therapy, including hormone type, on biennial questionnaires from 1989 to 2001. Among 7341 postmenopausal women reporting no UI in 2001, we identified 1026 women who developed UI at least monthly between 2001 and 2003. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).Women currently using hormone therapy had 1.39-fold (95% CI, 1.16-1.67) increased odds of incident UI, compared with women who never used hormone therapy. ORs were similar in current users of oral estrogen alone (OR, 1.35, 95% CI, 1.03-1.78) and oral estrogen with progestin (OR, 1.37, 95% CI, 1.13-1.67).These findings suggest an increased risk of UI associated with use of postmenopausal hormone therapy in younger postmenopausal women.