Objectives: Dose-finding trials are fundamental to develop novel drugs for children and adolescents with advanced cancer. It is crucial to maximise individual benefit, whilst ensuring adequate assessment of key study end-points. We assessed prognostic factors of survival in paediatric phase I trials, including two predictive scores validated in adult oncology: the Royal Marsden Hospital (RMH) and the MD Anderson Cancer Center (MDACC) scores. Methods: Data of patients with solid tumours aged = 1 correlated with worse OS in the multivariate analysis. The RMH and MDACC scores correlated with OS in adolescents (12-17 years), p = 0.002, but not in children (2-11 years). Conclusions: Performance status of 90-100% and school/work attendance at enrolment are strong indicators of longer OS in paediatric phase I trials. Adult predictive scores correlate with survival in adolescents. These findings provide a useful orientation about potential prognosis and could lead in the future to more paediatric-adapted eligibility criteria in early-phase trials. (C) 2016 Elsevier Ltd. All rights reserved.