Objective: In patients with tetralogy of Fallot, infants less than 12 months old and children between one and four years old were compared after total repair surgery for determination of outcome of surgery, risk factors influencing mortality and morbidity. Methods: Fifty- two patients with tetralogy of Fallot between five months and four years of ages were included into the study. The patients were divided into two groups depending on their ages; Group 1; one year old and younger (n=21) whereas, group 2; one and four years old (n=31). Statistical analysis was performed using Mann-Whitney U, Chi-square or where appropriate Fisher’s exact tests and logistic regression analysis was applied for determination of predictors of mortality. Results: The parameters that were different between two groups include; age (Group 1; 10.00±1.67 months and Group 2; 2.39±0.77 years, p<0.001), weight (Group 1; 9.74±2.23 kg, Group 2; 11.97±1.78 kg, p<0.001), McGoon ratio (Group 1; 1.94±0.29, Group 2; 2.19±0.27, p=0.001). Mortality is found in 3 patients in group 1 (14.2%) whereas, in five patients in group 2 (16%) and the difference was not statistically significant. In group 2 in only one patient (0.03%) had complete atrioventricular block and required permanent pacemaker implantation. When patients were compared according to groups with and without mortality, the significant differences were found in following variables: peritoneal dialysis (p=0.001), pleural effusion (p=0.02), right ventricular pressure (p=0.001) and right ventricle/aorta pressures ratio (p=0.001). However, none of these risk factors had significant value in prediction of mortality. Conclusion: Depending on these results, in patients under one year of age with symptomatic tetralogy of Fallot, if there are no other pathologies that have potential to increase risk of mortality, the complete repair surgery can be performed with same amount of risks and similar morbidity and mortality ratios.