OBJECTIVE: The authors examined gender differences in response to tricyclic antidepressants. METHOD: A total of 30 randomized, placebo-controlled trials that included 3,886 patients (1,555 men and 2,331 women), submitted between 1979 and 1991 in order to obtain marketing authorization, were reviewed. Gender differences in response to treatment were tested in various multiple regression models using a variety of response definitions. RESULTS: Different response definitions all pointed to no gender difference in the efficacy of tricyclic antidepressants. The estimated effect size was similar for women younger and older than age 50 and for men. CONCLUSIONS: Tricyclic antidepressant response is independent of gender.