Objective: To report the results of pulse oximetry screening for congenital heart diseases in healthy newborns during the transitional period between birth and discharge. Those with positive screening results were referred for echocardiographic evaluation aimed at a specific diagnosis. Materials and methods: A retrospective, descriptive, observational and cross-sectional study. Data were obtained from screening 4,897 newborns who were admitted to the nursery of the Obstetrics and Gynecology Unit at Hospital Universitario de Guayaquil, within the first 24 hours of birth, all diagnosed as healthy newborns. As part of the protocol, cardiac screening was performed on all newborns at admission and discharge. Newborns with saturation levels below 95 % on pulse oximetry underwent consecutive measurements at one-hour intervals, with a total of three readings. Additionally, those with more than a...