OBJECTIVE: Although congenital cytomegalovirus (cCMV) is the most common congenital infection world-wide, many infected infants are not diagnosed at birth. Anticipating that infants with cCMV who are not tested at birth risk a delayed diagnosis, this study was conducted to investigate the timing of diagnosis for infants with cCMV and to determine the reasons for and impact of late diagnoses. METHODS: Clinical, imaging and laboratory data, hearing and developmental outcomes were abstracted from medical records between 2009 and 2021 for infants with virologically confirmed cCMV. RESULTS: One hundred and twelve children with confirmed cCMV were identified. Diagnosis was within the first three weeks of life for 60 (54%) (early diagnosis group/EDG) and after this time for 52 (46%) (late diagnosis group/LDG). Infants in the LDG were diagnosed via CMV PCR on neonatal dried blood spot specimens with the majority (71%) tested after identification of sensorineural hearing loss (SNHL). The median time to first CMV testing in the LDG was 12 (IQR 3-42) months. Symptoms consistent with cCMV were present at birth in 17 (33%) of the infants with delayed diagnosis. More infants in the EDG received antiviral treatment ( CONCLUSION: The lack of formal protocols for cCMV testing leads to delayed diagnoses for many infants. This delay results in missed opportunities for monitoring, intervention, and treatment.