ADMA levels are significantly elevated in RA patients compared to controls.CRP is the independent predictor of elevated ADMA and 8-iso-PGF2α levels.Positive correlation between oxidative stress (8-iso-PGF2α) and inflammation in RA.High disease activity in RA (DAS28 score 5.2 ± 1.1) is associated with increased biomarkers of endothelial dysfunction. This evidence concerns the gene CRP and endothelial dysfunction.