Unilateral agenesis of the pulmonary artery is a rare congenital anomaly that is commonly associated with ventricular septal defect (VSD). Its clinical presentation is diverse, and if left untreated, it can lead to significant damage and even death. Several surgical techniques have been developed for its management, with variable results. We report the case of a 2-month-old infant with agenesis of the left pulmonary artery (PA) and VSD. One-stage primary surgical re-anastomosis was successful in establishing continuity to the main PA and preventing further damage to the heart.