Background: Congenital heart defects (CHD) are among the most common congenital diseases with great impact in infantmorbidity and mortality; however, their real incidence in our country is unknown. The Ministry of Health created the NationalCongenital Heart Defect Program to contribute to the reduction of infant mortality for this cause. Therefore, determiningthe incidence and the relative frequency of CHD at the Hospital Materno Infantil Ramon Sarda, a public tertiary institutionspecialized in high risk pregnancies and congenital defects would provide information to the Program.Objectives: 1) To determine the incidence and relative frequency of CHD in liveborn (LB) infants at the Hospital MaternoInfantil Ramon Sarda in the beginning of the PNCC program. 2) To evaluate the association with other congenital defects.3) To analyze the distribution of CHD by sex.Methods: The study has a descriptive, observational and retrospective design. The digital clinical records of 1,161 LB infantswith confirmed diagnosis of CHD from the Section of Pediatric Cardiology, Hospital Materno Infantil Ramon Sarda, betweenJanuary 1, 1998 and December 31, 2011, evaluated during hospitalization and follow-up at the outpatient clinic, were analyzed.Congenital heart defects were classified based on their severity according to the meta-analysis published by Hoffman andKaplan in USA assessing their incidence and relative frequency.Categorical data are presented as number of absolute cases and percentage. Results: From a total of 92,725 LB infants during the study period, CHD were present in 1,161 of cases (12.5/1000). Afterexcluding small muscular ventricular septal defects, the prevalence decreased to 7/1000 LB infants.The prevalence of moderate and severe CHD was 44% (3 to 3.5/1000).Ventricular septal defects were the most common CHD.Conclusion: Despite being a tertiary center for high risk pregnancy and congenital defect, the incidence of CHD determinedat the Hospital Materno Infantil Ramon Sarda is similar to the one published worldwid