Background: Polycystic ovary syndrome (PCOS) affects 5%-15% of women and is the most common cause of hirsutism. Data on the time-course of improvement to suppressive therapy and predictors of that response in PCOS are lacking. The objectives of our study are to determine the long-term response and identify predictors of response in PCOS women treated with suppressive therapy, including spironolactone (SPL) + oral contraceptives (OCs). Materials and Methods: Retrospective cross-sectional analysis of 200 women with PCOS (1990 NIH criteria) treated with suppressive therapy in general, and a subgroup of 138 subjects treated with OCP+SPL who had been prospectively included in a biorepository. Main outcome measure included improvement rate per 100 person-month of follow-up for hirsutism, menstrual irregularity and acne measured qualitatively as "feeling better", and changes in the severity of hirsutism quantified by modified Ferriman-Gallwey [mF-G] score. Results: During a mean follow-up of 34.2 months, 85.1%, 82.7%, and 79.3% of patients reported improvement in hirsutism, menstrual dysfunction, and acne, respectively. The modified Ferriman-Gallwey (mF-G) hirsutism score improved by 59.9%. The net reduction in mF-G score and the percent of patients reporting improvement in hirsutism were greater for OC+SPL than for either drug alone, with no difference in the percent of patients free of adverse effects. Among those treated with OC+SPL (n = 138), the initial mF-G and sex hormone-binding globulin (SHBG) independently predicted successful therapy for hirsutism. Conclusion: There is a high rate of patient satisfaction with suppressive therapy in PCOS. The efficacy of suppressive therapy for hirsutism was greater with OC+SPL than with either drug alone. Successful treatment of hirsutism with combination OC+SPL requires at least 6 months of therapy, with the proportion of satisfied patients continuing to increase with treatment duration. The probability of patient satisfaction with OC+SPL treatment for hirsutism can be predicted by her initial mF-G score or SHBG level.