Introduction: Congenital malformations are the leading cause of early neonatal mortality and the second leading cause of infant mortality. Among them, congenital heart diseases are the main cause of mortality in the early neonatal period. Material and methods: A prospective cross-sectional study was conducted at the "Dr. Ovidio Aliaga Uría" Children's Hospital in La Paz, Bolivia, at an altitude of 3,650 masl. A pediatric cardiology outpatient clinic was set up to examine 42 children, recording clinical data, physical examination, and color Doppler echocardiography. Results: The most frequent reason for referral was a heart murmur. In 52.38% (n=22) of the evaluated patients, congenital heart disease was present, with ventricular septal defects being the most common at 40.91% (n=9), followed by atrial septal defects at 18.18% (n=4), persistent foramen ovale at 13.64% (n=3), and patent ductus arteriosus at 9.09% (n=2) of patients. Discussion: There are very few studies in populations living at altitudes above 3,000 masl. Our study shows a high percentage of children with cardiac defects, which may be attributed to accurate diagnosis at referral or possibly a higher incidence of cardiac malformations in the studied population. Conclusion: the most common cardiac defect was ventricular septal defect, as described in populations living at sea level.