OBJECTIVE: Rheumatoid arthritis (RA) is characterized by the interaction of multiple mediators, especially cytokines. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine and has been shown to be involved in RA. This study explored the association of the MIF gene polymorphism with RA in Korean. METHODS: 114 patients with RA, and 114 age and gender matched healthy controls were studied. Patients and controls were genotyped for a single nucleotide polymorphism (SNP) in the 5'-flanking region at position -173 of the MIF gene. RESULTS: No significant differences in MIF gene polymorphism were observed in RA compared to healthy controls. No association with disease severity was detected for the MIF gene polymorphism. CONCLUSION: MIF -173 G/C polymorphism did not appear to be associated with genetic susceptibility and disease severity in Korean RA patients.