Objectives This study aimed to describe the incidence and spectrum of postoperative complications in infants who underwent their first cardiac surgery for the repair of congenital heart diseases. Methods This is a single-center retrospective study. Data of infants admitted to King Faisal Specialist Hospital & Research Center; Jeddah; Saudi Arabia, from January 2015 to December 2019 who underwent the first cardiac procedure for congenital heart disease at an age of less than 3 months, were analyzed. The primary outcome is the prevalence and spectrum of postoperative complications during hospitalization. Data were analyzed by using descriptive and analytical statistics using SAS software version 9.4. Results Data of 130 procedures were analyzed. The most frequent procedure performed was the Norwood procedure (31.5%), aortic coarctation repair (13.8%), arterial switch operation (13%), and Blalock-Taussig and central shunts (10%). The overall postprocedural complications were reported in 96 (73.8%) of the procedures. The most frequent complications were prolonged postoperative mechanical ventilation (27%), pleural effusion (21%), excessive bleeding (19%), cardiac arrest (18%), and systemic infections (18%). Conclusion Cardiac surgery for congenital heart disease in young infants has a substantial risk for postoperative complications. The high incidence of these complications in these cases makes necessary attention to prove the outcomes in the cardiac centers.