Background: The aim of this study was to assess the relation between plasma B-type natriuretic peptide (BNP) levels and right ventricular function evaluated by tissue Doppler imaging (TDI) in patients after repair of tetralogy of Fallot (ToF). Methods: Twenty-five patients with a mean age of 14.1 ± 4.4 years who underwent repair of ToF at a mean age of 4.9 ± 5.1 years enrolled in this study. The control group consisted of 29 healthy children at a mean age of 13.1 ± 2.8 years. The right ventricle and pulmonary regurgitation (PR) were assessed by two-dimensional echocardiography and color Doppler. Blood samples for BNP levels were taken and TDI was performed at rest. Results: Plasma BNP levels were significantly higher in patients than in controls (28.3 ± 24.1 vs. 7.4 ± 2.3 pg/mL, P = 0.0001). The myocardial performance index (MPI) (1.08 ± 0.35 vs. 0.58 ± 0.11, P = 0.0001) was higher and isovolumic acceleration (IVA) (3.1 ± 0.7 vs. 5.4 ± 1.0 m/s2, P = 0.0001) was lower in patients. The correlations were also significant between the degree of PR and MPI (r = 0.7, P = 0.0001) and also IVA (r = -0.7, P = 0.0001). The correlations were also significant between the BNP level and MPI (r = 0.6, P = 0.0001), IVA (r = -0.4, P = 0.002) and the degree of PR (r = 0.6, P = 0.0001). Conclusion: As a result, plasma BNP level increases in patients with ToF and both MPI and IVA from the right ventricular basal segments might be used to assess the right ventricular function. © 2009, Wiley Periodicals, Inc.