Monocyte chemoattractant protein-1 (MCP-1) is a pivotal chemokine in the inflammatory response, which plays an important role in recruiting monocytes to sites of injury and infection. However, the exact mechanism of Mcp-1 associated with PCOS risk was unknown. In this study, we explored whether the Mcp-1 -2518G>A polymorphism increases the risk of PCOS. We performed a comparative study of -2518G>A polymorphism of the Mcp-1 gene with PCOS. In addition, luciferase reporter assay was performed to evaluate the Mcp-1 transcriptional activity. A strong association was observed between the -2518G>A polymorphism of Mcp-1 gene and PCOS (p-value = 0.016, odd ratio (OR) = 0.693). A p-value under 0.05 is considered statistically significant. The genotype and allelic frequencies were assumed to be in Hardy-Weinberg equilibrium (HWE). The luciferase assays in 2 cell lines showed that the Mcp-1 -2518G>A substitution can increase the expression of Mcp-1. MCP-1 levels in serum for PCOS group were significantly higher than those in serum for controls (p-value = 0.02). Furthermore, the patients carrying a genotype A/A had significantly increased levels of MCP-1 in serum compared with levels of the MCP-1 of the patients with genotypes G/G and G/A (p-value = 0.031). This is the first study on the genetic variation of the Mcp-1 gene and PCOS. This finding suggests that the Mcp-1 -2518G>A polymorphism is associated with PCOS risk by affecting transcriptional activity, leading to an increased expression level of Mcp-1.