Background: Critical congenital heart disease (CCHD) remains significant clinical and public health challenge. Risk of morbidity and mortality in CCHD increases when there is a delay in diagnosis and referral to a tertiary center with expertise in treating these patients. In the last few years, pulse oximetry screening for CCHD in newborns has been added to the list of recommended uniform screening panels and advocated by several health-care authorities. Early detection of CCHD by using pulse oxymetry was recommended by American Academy of Pediatrics (AAP), the American Heart Association, and the American College of Cardiology to improve early identification of infants with CCHD. Objective: To describe early versus late diagnosis of critical congenital heart disease (CCHD) at single tertiary center. Methods: A retrospective observational study was conducted in Sanglah Hospital, Bali. Data collected from medical records. Early diagnosis defined as diagnosis which made during prenatal examination or before birth hospital dischare. Late diagnosis defined as diagnosis which made after birth hospital discharge, after 3 days of birth, or even at death. Diagnosis of CCHD was retrieved based on echocardiography examination. Results: From June 2016 to February2020 we found 86 CCHD cases which were tetralogy of Fallot (41 cases), pulmonary atresia (15 cases), transposition of great arteries (14 cases), total anomalous pulmonary venous return (4 cases), tricuspid atresia (3 cases), truncus arteriosus (3 cases), and hypoplastic left heart syndrome (1 case). Only 26% cases of children with CCHD were diagnosed early, mostly came with chief complaint bluish appearance. Range of oxygen saturation at diagnosis varied from 51-90%. Among cases with late diagnosis, the most common defect was tetralogy of Fallot. Most late diagnosed CCHD came because of referral from other hospitals or pediatricians. Conclusion: The rate of delayed CCHD diagnosis still occurs in 74%. Factors that might be contribute to late CCHD diagnosis include certain CCHD types, nontertiary hospital nursery and absence of clinical findings.