The aim of the study was to asses right ventricular function by tissue Doppler imaging (TDI) in asymptomatic patients with repaired tetralogy of Fallot. Methods: The study group consisted of 20 children 7-18 years after surgical treatment, in whom echocardiographic parameters and TDI values were analyzed. Patients were divided into two groups according to the level of pulmonary regurgitation (PR). The group 1. consisted of 9 children with mild/moderate PR, the group 2 consisted of 11 patients with severe PR. Results: Patients in the group 1. had significantly higher systolic velocity , early diastolic velocity and late diastolic velocity comparing to the patients from the group 2. (14,1+/-1,3 vs 8,9+/-1,46; 13,8+/-0,9 vs 8,7+/-1,1; 15,3+/-1,2 vs 10,3+/-1,3 cm/s; respectively, p<0,05). Isovolumic relaxation time and isovolumic contraction time in the group 2 were significantly longer than those in children in the group 1 (85,6+/- 15 vs 57,6+/-12; 110+/-34 vs 78+/-19 ms, respectively; p<0,05). Duration of ejection time did not differ between both groups. Tei index was significantly greater in children of the group 2. than in patients of the group 1. (0.73+/-0.09 vs 0.54+/-1.0, respectively, p<0.05). Conclusions: Tissue Doppler imaging can be useful diagnostic tool of right ventricular function in children after tetralogy of Fallot correction. Systolic velocity, early diastolic velocity, late diastolic velocity are significantly higher and Tei index is lower in children with mild/moderate pulmonary regurgitation than in patients with severe pulmonary regurgitation, which can indicate right ventricular function disturbances.