Background: Acute rheumatic carditis is still an important cause of cardiac failure in developing countries. B-type natriuretic peptides, especially N-terminal segment of its prohormone are now recognised as essential parrs of cardiologic evaluation. Increased plasma concentrations of B-type natriuretic peptide and its prohormone are markers of cardiac failure and hypoxia in adults. Aim: To measure the prohormone levels in children with acute rheumatic carchtis and to determine whether its concentrations correlate with clinical and laboratory findings. Methods: A total of 24 children with acute rheumatic carchtis and 23 age and sex-matched healthy subjects were entered in the study. Transthoracic echocardiography was performed in all patients to assess the severity of the valve insufficiency and cardiac dysfunction. The prohormone plasma levels were tested for correlation with cardiac dysfunction and other biochemical markers, such as C-reactive protein, erythrocyte sedimentation rate, and anti-streptolysin-O titter. Results: The prohormone plasma concentrations were significantly higher in children with acute rheumatic carditis than in control subjects at the rime of diagnosis. A significant decrease of the plasma level was detected among patients after treatments (6-8 weeks). Conclusion: We found increased plasma prohormone levels in children with acute rheumatic carditis in the acute stage of illness compared with healthy subjects. Another result is increased plasma prohormone levels as acute rheumatic carditis are reversible.