The aim of the study was to assess the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and inflammatory markers in patients with congestive heart failure (CHF) treated with cardiac resynchronization therapy (CRT). 97 patients (age 54.9+/-9.9 years; 87% men) with implanted CRT devices (median period after implantation 19.9+/-19.3 months) were enrolled. According to NT-proBNP level patients were divided into tertiles: first (n=36) - less than 848 pg/ml, second (n=29) - from 848 to 2936 pg/ml, and third (n=32) - more than 2936 pg/ml. We didnt find a relationship between inflammatory mediators, NT-probNP level and time after implantation. In the total group NT-proBNP significantly correlated with structural and functional parameters of the heart. In the first group in comparison with the third group levels of IL-6 were lower (pI-III=0.019) and levels of IL-l - higher (pI-III=0.006). IL-10, CRP, TNF- did not differ between groups. In the first group IL-l straightly correlated with IL-6, TNF- , IL-10 and left ventricular ejection fraction (LVEF), in the third group IL-6 straightly correlated with CRP, while correlation of IL-l with LVEF became negative. We suppose that in patients with mild HF IL-l can play an adaptive role. High levels of IL-6, CRP probably can be used as markers of CHF progression in patients treated with CRT.