OBJECTIVE: To develop a self-administered questionnaire for measuring health-related quality of life (HRQL) in women with polycystic ovary syndrome (PCOS). METHODS: We identified a pool of 182 items potentially relevant to women with PCOS through semistructured interviews with PCOS patients, a survey of health professionals who worked closely with PCOS women, and a literature review. One hundred women with PCOS completed a questionnaire in which they told us whether the 182 items were relevant to them and, if so, how important the issue was in their daily lives. We included items endorsed by at least 50% of women in the analysis plus additional items considered crucial by clinicians and an important subgroup of patients in a factor analysis. We chose items for the final questionnaire taking into account both item impact (the frequency and importance of the items) and the results of the factor analysis. RESULTS: Over 50% of the women with PCOS labelled 47 items as important to them. Clinicians chose 5 additional items from the infertility domain, 4 of which were identified as important by women who were younger, less educated, married, and African-American. The Cattell's Scree plot from a factor analysis of these 51 items suggested 5 factors that made intuitive sense: emotions, body hair, weight, infertility, and menstrual problems. We chose the highest impact items from these 5 domains to construct a final questionnaire, the Polycystic Ovary Syndrome Questionnaire (PCOSQ), which includes a total of 26 items and takes 10-15 minutes to complete. CONCLUSIONS: We have used established principles to construct a questionnaire that promises to be useful in measuring health-related quality of life. The questionnaire should be tested prior to, or concurrent with, its use in randomized trials of new treatment approaches.