Objective: To evaluate the results of pulse oximetry screening in the Republic of Tatarstan from 2020 to 2022. We reviewed cases of newborns with positive screening results from 2020-2022 and specifically analyzed children with CCHD, examining hospitalization duration and timing of surgeries. Between 2020 and 2022, 116,408 births were recorded in Tatarstan, with 115,344 (99.08%) infants undergoing pulse oximetry screening. Of these, 1,466 (1.25%) had positive results. Among them, 175 (0.15%) were diagnosed with congenital heart defects, including 57 (0.04%) with critical CCHD. Additionally, 277 (0.24%) were found to have persistent pulmonary hypertension (PPHN), and 331 (0.28%) were diagnosed with pneumonia. We divided the children into three groups: I – those with CCHD detected prenatally by ultrasound, II – those diagnosed postnatally by pulse oximetry, and III – those diagnosed after discharge or transfer from the hospital. No statistically significant difference in the age at surgery was found between the prenatal and postnatal screening groups (p>0.05). However, the screening group underwent surgery significantly earlier than the delayed diagnosis group (p<0.05). Adding pulse oximetry to prenatal screening detects over 30% more CCHD cases, allowing for earlier intervention. Children in the prenatal and postnatal screening groups had surgery at similar ages, while delayed diagnosis cases were operated on later, potentially leading to more severe disease progression and higher risk of fatal outcomes.