Vitamin D and omega-3 fatty acid co-administration significantly decreased serum high-sensitivity C-reactive protein (hs-CRP) (p = 0.001) and malondialdehyde (MDA) levels (p < 0.001), and significantly increased plasma total antioxidant capacity (TAC) levels (p = 0.003) compared with the placebo.Vitamin D and omega-3 fatty acid co-supplementation significantly downregulated gene expression of interleukin-1 (IL-1) (p = 0.03), and upregulated vascular endothelial growth factor (VEGF) (p = 0.004) in PBMCs of subjects with PCOS, when compared with placebo. The gene discussed is VEGFA; the disease is polycystic ovary syndrome.