This study aimed at examining the association of the single nucleotide polymorphism (SNP) in the protein tyrosine phosphatase gene (PTPN22) with the risk of rheumatoid arthritis (RA) in a Chinese population. A total of 200 RA patients and age and gender-matched healthy controls were recruited. Their genotypes and allelic frequency were determined by the TaqMan-MGB probe-based polymerase chain reaction (PCR). The frequencies of the CC genotype and C allele in RA patient group were significantly higher than that of controls (P < 0.01 or P < 0.05) with an odds ratio of 1.67, respectively. These data suggest, the CC genotype and C allele of the -1123G > C in the PTPN22 gene are associated with an increased risk for RA in Chinese population. Therefore, the CC genotype and C allele of the -1123G > C in the PTPN22 gene may be used as a genetic marker for the predisposition of RA in Chinese.