The presence of a reciprocal link between inflammation and oxidative/nitrosative stress has been postulated in chronic heart failure (CHF). We aimed to determine signs of nitrosative stress in serum/plasma of CHF patients. ELISA tests were used for quantification of serum/plasma levels of Nitrotyrosine (NT), H(2)O(2), total NO, nitrite (NO(2)(-)), myeloperoxidase (MPO), Tumor Necrosis Factor-alpha (TNFalpha) and pro-Brain Natriuretic Peptide (proBNP) in 66 CHF patients (9 in NYHA I, 34 NYHA II, 23 NYHA III) and in 14 age-matched healthy subjects. NT levels were higher in NYHA III CHF patients compared to NYHA II (p<0.05), NYHA I (p<0.03) and controls (p<0.02), whereas NO(2)(-) and total NO were higher in NYHA III compared to I (p<0.05 and p<0.04, respectively) and controls (p<0.004 and 0.002) and in NYHA II compared to controls (p<0.04 and p<0.009). NT levels correlated significantly with MPO (r=0.37, p<0.003), TNFalpha (r=0.32, p<0.01) and proBNP (r=0.32, p<0.01). These data demonstrate an increased NT plasma level in patients with moderate/severe CHF which is associated to increased levels of markers of systemic inflammation.