Aim Polycystic ovary syndrome (PCOS) is the most common endocrine disorder that women experience during their reproductive years and is associated with many psychiatric disorders. This study sought to determine the existence of psychiatric disorders in women with untreated PCOS. Another objective of the study was to examine whether an association exists between psychiatric disorders, insulin resistance, and body mass index. Material and Methods Women who met the Rotterdam criteria for PCOS (n=88) were included. Structured Clinical Interviews for the Diagnostic and Statistical Manual of Mental Disorders, 4th Edn were conducted. After the psychiatric evaluations, blood samples were obtained from the participants. Results Prevalence for all comorbid psychiatric disorders was 50% (n=44). The most common psychiatric disorder was major depression (33%), followed by generalized anxiety disorder (13.6%) and binge-eating disorder (6.8%). No significant difference in body mass index and insulin resistance index scores was found between women with and without psychiatric disorders (P>0.05 for both comparisons). Conclusion A considerable number of women with PCOS experience a psychiatric disorder during their lifetime. Clinicians should be aware that women with PCOS are at a high risk for major depression, generalized anxiety disorder, and binge-eating disorder.