Objective. This study aims to investigate the effect of combining calcium and vitamin D supplements with metformin on menstrual cycle abnormalities, gonadotropins, and IGF-1 system in vitamin D-deficient/insufficient PCOS women. Study Design. This is a randomized, placebo-controlled clinical trial. Setting. This study was performed in Damascus University of Obstetrics and Gynecology Hospital and Orient Hospital, in Damascus, Syria. Materials and Methods. Forty PCOS women with 25-OH-vitamin D