Between 2007-2010 the Child Protection Team (CPT) at University Children's Hospital Zurich was the first in Europe to follow up the development of maltreated children in a hospital sample . The follow-up took place 2-3 years after the child had been reported to the CPT. As a major result, children's health-related quality of life (HRQoL) had been impaired in maltreated children compared to controls (Jud, Landolt, Tatalias, Lach, & Lips, 2012). However, this difference only emerged for the self-assessment of HRQoL by children aged 6 years or older .To address limitations, the CPT at University Children's Hospital Zurich and Children's Hospital Baden AG propose a prospective study with a baseline at the time of report to the CPT and a two year follow-up. This study aims at analyzing HRQoL, behavior and mental health of maltreated children prospectively and will be the first to provide data on changes in HRQoL in the aftermath of maltreatment. We assume the following hypotheses: