Extracorporeal life support (ECLS) has been used in 10 patients after heart (5 patients), lung (3 patients), and heart-lung (2 patients) transplantation. The age range was 7 months to 55 years. Cardiopulmonary failure leading to institution of ECLS was due to acute postoperative organ malfunction in 4 patients (2 survived), subacute organ malfunction in 3 patients (none survived), and late rejection or infection in 3 patients (2 survived). Neurologic complications occurred in 3 patients (1 survived) and bleeding, in 5 patients (2 survived). Six patients (60%) were successfully weaned from ECLS, and 4 (40%) survived to leave the hospital. Survival was associated with younger age, shorter duration of ECLS, and longer interval from operation to initiation of ECLS but not to reason for initiating ECLS. Extracorporeal life support is feasible for sustaining both adults and children after heart, lung, or heart-lung transplantation. Best results were obtained in patients with conditions that, in retrospect, were treatable and reversible within days. More experience is needed to predict preoperatively which patients will benefit most from ECLS.