Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity and mortality attributed to traditional cardiovascular risk factors and/or the chronic systemic inflammation. We investigated the effect of a TNF antagonist (adalimumab-ADA) on aortic stiffness in RA patients. We studied 18 RA patients with active disease despite therapy with disease modifying antirheumatic drugs (DMARDs), treated with ADA (alone or in combination with DMARDs) for 12 weeks. Disease activity markers as well as aortic stiffness indices (carotid-femoral pulse wave velocity-PWV, augmentation index-AIx), were measured at baseline and at the end of treatment. Eighteen RA patients treated with methotrexate (MTX) were included as controls. Patients were categorized as responders (decrease of Disease Activity Score-DAS28 > 1.2) or nonresponders. There was a statistically significant decrease in PWV (from 8.18 ± 2.03 to 7.01 ± 1.78 m/s, p = 0.00006) and DAS28 (from 6.65 ± 1.22 to 4.69 ± 1.46, p = 0.00007) in RA patients treated with ADA. The decrease in PWV was observed both in responders (n = 12) and nonresponders (n = 6). Multivariate analysis showed that the decrease of PWV was independent of changes in disease activity or other parameters. There was no significant change in PWV in patients treated with MTX (from 8.87 ± 1.91 to 8.41 ± 2.17, p = 0.29). No significant change in AIx or traditional cardiovascular risk factors was observed. Treatment with ADA significantly reduced aortic stiffness in RA patients regardless of their response to therapy. These findings imply a direct protective effect of ADA in vascular wall in RA patients.