- To evaluate aortic stiffness by MRI in female patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) in comparison to controls. We measured aortic strain, distensibility and pulse wave velocity (PWV) by MRI in 30 SLE patients, 31 RA patients and 53 matched controls. Mean PWV in SLE and RA patients were higher in comparison to controls (9.2 ± 4.4 vs. 7.6 ± 3.0 m/s, p = 0.04) and (6.2 ± 2.3 vs. 5.4 ± 1.7, p = 0.04) respectively. Aortic distensibility among RA patients was significantly lower in comparison to controls (4.4 ± 4.6 vs. 5.8 ± 4.9 kPa−1 × 10−3, p = 0.04). A significant correlation was found between PWV and age (r = 0.67, p < 0.001), Framingham risk score (r = 0.61, p < 0.001), waist to hip ratio (r = 0.45, p < 0.001), systolic blood pressure (r = 0.37, p = 0.01), diabetes (r = 0.32, p = 0.001) and dyslipidemia (r = 0.32, p = 0.001). In multivariate analysis for the prediction of PWV, variables which were found significant included: RA (p = 0.01), age (p < 0.001) and hypertension (p = 0.01) for patients with RA and SLE (p = 0.02), waist to hip ratio (p < 0.001) and total cholesterol (p < 0.001) for patients with SLE. Arterial stiffness, characterized by metrics of aortic distensibility and pulse wave velocity derived from MRI, is increased in SLE and RA female patients.