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 (Jud, Lips, & Landolt, 2010). Out of a total 180 children in the 2005/2006 CPT caseload, 42 children between 2.5 and 16.5 years and their primary caregiver participated (Jud, Lips, et al., 2010). The follow-up took place 2-3 years after the child had been reported to the CPT. Non-CPT reported hospital patients were used as controls, matched for age, gender, nationality, and medical condition. 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 (Jud et al., 2012). The assessment of children's HRQoL by primary caregivers showed no significant differences for maltreated children compared to controls for all age groups. An essential lack of understanding of the child's experiences and beliefs is not only likely to affect the child's HRQoL, but may also contribute to cur-rent and future risk of maltreatment (Jud et al., 2012). Furthermore, maltreated children had increased depression scores and more behavior problems compared to controls. Detailed results can be found in Jud et al. (Jud et al., 2012; Jud, Lips, et al., 2010). To address these 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. Based on a literature review and findings of the previous follow-up study, we assume the following hypotheses: