BACKGROUND: Rheumatoid arthritis (RA) is a widely recognized cause of carpal tunnel syndrome (CTS). Others stated that CTS is overestimated in RA. CTS is associated with increase in the thickness of the median nerve. This study aims to establish the determinants of the median nerve cross sectional area (MNCSA) in RA patients with no CTS. METHODS: Ultrasound measurements were performed in 120 RA patients (240 hands)without symptoms or diagnosis/previous diagnosis of CTS. Eachmedian nerve was measured three times, and the mean value was used for analyses. RESULTS: MNCSA was 9.79plusmn2.6 mm2 (range 1.5-22.25). MNCSA was positively associated with the age of participants (p=0.03, CI:0.00-0.08), body mass index (BMI) (p=0.04, CI:0.00-0.21), uric acid level (p=0.033, CI:0.00-0.01), and urine microalbumin (p=0.04, CI:0.00-0.01). RA clinical characteristics and inflammatory markers showed no significant relation to the MNCSA. CONCLUSION:MNCSA in RA is affected by age, BMI, serum uric acid and microalbumin level.