Abstract: OBJECTIVE To investigate the single nucleotide polymorphisms(SNP) of the microRNA-146a (miR-146a) in rheumatoid arthritis(RA), and whether it is associated with clinical manifestations and the serum tumor necrosis factor-α(TNF-α) level in patients with RA. METHODS The SNP of miR-146a rs2910164 polymorphism was detected by high-resolution melting method in 126 patients with RA, and the serum TNF-α level was detected by enzyme linked immunosorbent assay(ELISA). The correlations of miR-146a rs2910164 polymorphism with clinical manifestations and the serum TNF-α level were also analyzed. RESULTS The percent of RA patients with G/C, G/G and C/C genotype was 35.7%, 12.7% and 51.6% respectively. It was not found that any significant association of miR-146a rs2910164 polymorphism with disease activity in RA. However, the percent of RA patients with extraarticular manifestations was higher in miR-146a rs2910164 G/C genotype than in RA patients with other genotypes (P<0.05), and the serum level of TNF-α was higher in miR-146a rs2910164 G/C genotype than in RA patients with other genotypes(P<0.05). CONCLUSION It suggests that miR-146a rs2910164 polymorphism might correlate with special clinical manifestations and higher levels of serum level of TNF-α in RA, which indicate that miR-146a may play an important role in pathogenesis of RA.