Extracorporeal photopheresis (ECP) is a difficult procedure to perform in the pediatric population. This is a retrospective review of 12 pediatric patients who underwent photopheresis with the Therakos Cellex system for graft-versus-host disease (GVHD). Acute GVHD (aGVHD) occurred in 6 patients, and overlap syndrome and chronic GVHD (cGVHD) occurred in 4 and 2 patients, respectively. The ECP regimen was the same for all aGVHD and cGVHD patients: initially, every week (2 sessions/wk) for 2 months; next, every 2 weeks for 2 months; and finally, every month for at least 1 year. Improvement was observed in 7 of 10 aGVHD patients (70%) and in 4 of 6 cGVHD patients (66%). Eleven patients had skin involvement before ECP; 9 of them responded to treatment (81%). Gastrointestinal involvement occurred in 8 patients; 5 of them experienced improvement during ECP treatment (62%). All 4 patients with liver involvement failed to respond. No serious adverse reactions occurred. In conclusion, our study demonstrates that ECP with the Therakos Cellex system is a safe treatment option for GVHD in children, allowing the tapering of immunosuppressants by at least half.