This book gives an outline of the current discussion surrounding the diagnostic criteria for PTSD in children and the extent to which revised criteria may be included in the DSM-V. The role that the ICF (International Classification of Functioning, Disability and Health) may play here is emphasized, with particular attention to its central concept - functioning - in children with PTSD. The ICF is described and the first steps necessary for its implementation in this field are outlined. Based on an extensive review of the literature, a list of items considered important for the diagnosis is compiled and implemented in two case studies, taken from the Center for Psychotraumatology at Alexianer-Hospital Krefeld, Germany. The authors conclude that the ICF offers an important framework in which to view and assess children with PTSD and should therefore be used to complement the DSM-V. Several steps remain to be taken towards its implementation in this field to be able to fully draw on the advantages it offers in the diagnostic and therapeutic process.