The prognosis after relapse of high-grade osteosarcoma is poor and complete resection of all tumors is essential for survival. A 6-year old was diagnosed with high-grade osteosarcoma and treated according to the COSS-96 protocol. Within 5 years from initial diagnosis, five osteosarcoma relapses occurred and every time it was possible to achieve complete surgical remission. Additional treatments included chemotherapy and dendritic cell-based cancer immune therapy. Since the end of therapy of the 5th relapse, he is alive for 11½ years. Our experience further supports that aggressive surgery can help to achieve long-term survival even in patients with multiple osteosarcoma relapses. Pediatr Blood Cancer 2015;62:529–530. © 2014 Wiley Periodicals, Inc.