Polycystic ovary syndrome (PCOS) is a neuroendocrine disorder that commonly causes anovulation and infertility worldwide. Aside from infertility, patients with PCOS suffer from sleep disturbances and mental health issues. Recent studies have shown that functional foods may have a beneficial impact on psychological disorders and sleep quality. Therefore, the present study aimed to investigate the effects of daily intake of a fortified yogurt on the psychological and sleep profiles of women with PCOS. In this 8-week randomized double-blind controlled trial, after a 2-week run-in period, participants in the intervention group (n=45) received yogurt fortified with 10