The aim of this study was to evaluate the antitumor effect and toxicity of a single course of Peptichemio at high dose (450 mg/sq m) given to children with neuroblastoma resistant to first line treatment or at relapse. A total of 28 children were treated. Seven children showed partial response, 4 minor response, 8 had stable disease, and in 8 the tumor progressed. The principal toxic effect was myelosuppression. Hemorrhagic enteritis with liver failure and toxic death occurred in 1 patient. High dose Peptichemio can be administered with tolerable toxicity, inducing tumor regression in one third of previously treated patients.