In this prospective study, we aimed to assess left and right ventricular function in terms of the presence of right bundle branch block (RBBB) in the cases with repaired ventricular septal defect (VSD). Fifty-three patients who had VSD surgery at least 1-year preceding admission and 52 healthy controls were enrolled into the study. All the participants underwent electrocardiographic and echocardiographic examination. The cases with RBBB were determined. The conventional and tissue Doppler echocardiographic measurements of the patients with and without RBBB were compared with each other and healthy controls. Twenty-eight of VSD repair groups were male and 25 were female. Control group consisted of 30 males and 22 females. The mean age of the study and control groups was 7.5 ± 5.0 and 6.9 ± 4.3 years, respectively. RBBB was detected in 20 of 53 (37.7 %) operated patients. The only significant difference between the cases with and without RBBB was decreased right ventricular fractional area change (%) in the former group (33 ± 7 vs. 39 ± 5 p < 0.05). When compared to controls, operated group had statistically higher tricuspid annular plane systolic excursion (p < 0.05), lower systolic, early diastolic, and late diastolic myocardial velocities, higher left and right ventricular myocardial performance indices, irrespective of the presence of RBBB. The ratios of mitral or tricuspid inflow to left or right ventricular myocardial in early diastolic velocities measured from lateral annular levels were increased in operated group (all p values <0.05). In conclusion, RBBB in the cases with surgical VSD repair might be associated with right ventricular dysfunction. Biventricular systolic and diastolic dysfunction may develop following VSD repair irrespective of the presence of RBBB. Tissue Doppler-derived myocardial performance indices are useful in detection of those subclinical dysfunctions.