The purpose of this document is to recommend international standards for, and promote harmonisation of, the nonclinical safety assessments to support the development of pharmaceuticals intended for pediatric use. Harmonisation of the guidance for nonclinical safety studies will define the current recommendations and reduce the likelihood that substantial differences will exist among regions. It should facilitate the timely conduct of pediatric clinical trials and reduce the use of animals in accordance with the 3R (replace/reduce/refine) principles.