As a candidate gene for type 2 diabetes (T2D), insulin receptor substrate-1 (IRS‑1) gene variations were found to be associated with the risk of T2D. The aim of our study was to investigate the contribution of promoter DNA methylation of the IRS‑1 gene to the risk of T2D. Using bisulphite pyrosequencing technology, the DNA methylation levels of 3 CpG dinucleotides within the IRS‑1 gene promoter were measured in 48 T2D patients and 48 age‑ and gender‑matched healthy controls. Our results indicated that there was no significant association between the methylation of the IRS‑1 gene promoter and the risk of T2D (P>0.1). A breakdown analysis by gender revealed that IRS‑1 promoter methylation was not associated with an increased risk of T2D for either gender (P>0.1), although there were significantly lower methy-lation levels of CpG1 (P=0.002) and CpG2 (P=0.043) within the IRS‑1 gene promoter in males than in females.