OBJECTIVE To study the association between the single nucleotide polymorphisms (SNPs) in the high-temperature requirement A-1 (HTRA1) gene and rheumatoid arthritis (RA) in Chinese Han population. METHODS Five SNPs in the HTRA1 gene (rs2014307, rs2248799, rs2300433, rs714816 and rs2268356) were genotyped by ABI Snapshot method in Han Chinese cohort composed of 344 patients with RA and 288 healthy controls. The serum rheumatoid factor (RF) and C-reactive protein (CRP) of the patients were determined by endpoint nephelometry method. RESULTS Genotypes of all the five SNPs in the HTRA1 gene were not significantly different between the RA patients and controls (P> 0.05). Haplotypes generated by these five SNPs did not show significantly difference between the two groups either (P> 0.05). Serum RF levels in the RA patients had no significant difference among the genotypes for four SNPs (rs2014307, rs2248799, rs714816, and rs2268356) in the HTRA1 gene, while RF levels in the RA patients with genotypes AA+AG of the rs2300433 locus were significantly higher than that in genotype GG carriers (P< 0.05). Serum CRP levels in the RA patients had no significant difference among the genotypes for all the five SNPs. CONCLUSIONS Author's results suggested that although the five SNPs in the HTRA1 gene were not associated with RA in Chinese Han population, RF levels in the RA patients with genotypes AA and AG in the rs2300433 locus were significantly higher than the GG carriers. The HTRA1 role in RF regulation needs to be further investigated.