Inflammatory cytokines have been associated with the pathophysiology of hypertension and target organ damage (TOD). Resistant hypertensive patients (RHTN) are characterized by poor blood pressure control and higher prevalence of TOD. This study evaluated the relationship between plasma levels of TNF-α and arterial stiffness (pulse wave velocity - PWV) in 32 RHTN and 19 normotensive subjects. Moreover, we investigated the effect of TNF-α inhibition on human endothelial cells (HUVECs) incubated with serum from RHTN and normotensive subjects. HUVECs containing serum obtained from normotensive n=8 and hypertensive n=8 individuals were treated with TNF-α inhibitor (infliximab). Cell suspensions were used for measurement of DNA fragmentation and reactive oxygen species (ROS) content. RHTN patients showed higher levels of TNF-α compared to normotensive subjects, as well as higher PWV. Positive correlation was found between TNF-α levels and PWV measures in the whole group. HUVECs incubated with serum from RHTN showed increased cell apoptosis and higher ROS content compared to normotensive subjects. Infliximab attenuated the apoptosis of HUVECs incubated with serum from RHTN, but no effect in ROS production was observed. Our findings suggest that TNF-α might mediate, at least in part, vascular damage in resistant hypertension.