OBJECTIVE: We assessed the contribution of genetic polymorphisms of glutathione S-transferase M1 (GSTM1), T1 (GSTT1), and P1 (GSTP1, Ile105Val) to carotid atherosclerosis in 40 postmenopausal rheumatoid arthritis (RA) women without histories of smoking. METHODS: We measured mean intima-media thickness (IMT) and plaque of the common carotid arteries by ultrasonography, and evaluated relations among the known risk factors for atherosclerosis, genetic polymorphisms, RA outcomes and markers of inflammation. RESULTS: Subjects with the GSTT1-null genotype had greater IMT (p<0.05). On univariate analysis, carotid IMT was positively associated with age, systolic BP, antihypertensive drug use and the GSTT1-null genotype (p<0.05). When compared to subjects with a double- positive GSTM1/T1 genotype, IMT in subjects with concurrent lack of the GSTM1 and GSTT1 gene was significantly increased (p=0.008). CONCLUSION: This study suggests that the GSTT1-null genotype might have an interaction with carotid atherosclerosis related to RA in Korean postmenopausal RA women free of smoking history.