Anticancer chemotherapy plays a key role in the treatment of cancer in children. Following its increased efficacy, three children out of four can now be cured. Nevertheless, given the fact that 25% of the children with cancer are not cured and chemotherapy-induced long-term side effects are numerous there is a need to keep developing new agents and new strategies to fight cancer. Moreover studies investigating off-patents drugs should be stimulated in paediatric oncology in order to improve our knowledge of "old" drugs. Here we will review the specificities of children as compared to adults in the context of clinical drug development and pharmacology research in paediatric oncology. Such a research is now encouraged and facilitated by a European regulation as well as by international consortia such as "Innovative Therapies for Children with Cancer" (ITCC).