Residual structural pathology after cardiac surgery for congenital heart disease may complicate postoperative recovery. Completion angiograms obtained in the operating room may facilitate early detection and therapy of residual structural abnormalities. Our objective here is to report our institutional experience performing completion angiograms after cardiopulmonary bypass surgery. Between October 2007 and August 2008, 31 patients underwent completion angiograms after 32 cardiac surgical procedures. The median age was 7.5 months (range, 50 days to 31.2 years) and the median weight was 6.5 kg (range, 3.1-153 kg). Type of procedure, angiographic findings, and therapeutic decision were retrospectively reviewed. Procedures (proc) evaluated through completion angiography included comprehensive stage II or Glenn (n = 13), aortic arch reconstruction/conduit (n = 3), repair/palliation of tetralogy of Fallot or pulmonary atresia with ventricular septal defect (n = 4), PVR or conduit replacement (n = 5), and others (n = 7). Unexpected pathology was identified in 18 of 32 (56.3%) proc, which included left pulmonary artery (LPA) stenoses (n = 15), right pulmonary artery (RPA) stenoses (n = 11), and stenosis impairing coronary blood flow (after DKS; n = 1). In 9 of 32 (28.1%) proc, findings may have led to a change in therapeutic management. This included surgical revision (n = 1), 'Hybrid' therapy in the same setting (n = 2: LPA stent, 1; RPA balloon, 1), early catheterization within 3 months (n = 4), and change in medical management (n = 2: change in anticoagulation, 1; early CT, 1). Complications related to completion angiography were seen in only a single procedure (LPA staining). In conclusion, completion angiograms using a dedicated Hybrid cardiac operating suite may aid in early diagnosis and therapy of postsurgical abnormalities. They complement other methods of intraoperative imaging and may reduce the potential need for early surgical or transcatheter reintervention.