Abstract Background In the Netherlands, suspected cases of child maltreatment can be reported to an advice and reporting center on child abuse and neglect (Advies- en Meldpunt Kindermishandeling or AMK). AMKs investigate these reports, screen for problems in the family and its surroundings and refer to child welfare. Over the last decades the focus of AMK investigations has changed from an adult-only approach to a more child-oriented approach using a Child-Interview intervention. The effects and cost-effectiveness of AMK involvement in the Netherlands have never been studied. The primary aim of this study is therefore to examine the effect of the participation of maltreated children aged 6–18 years in the Child-Interview intervention on their mental health and quality of life. As a second aim, this study will examine the balance between additional costs and effects of the Child-Interview intervention in comparison with AMK investigation without the Child-Interview intervention (adult-only intervention). Design/Methods A quasi-experiment will be performed consisting of two post-intervention measurements of two nonequivalent groups: an intervention group, in which the Child-Interview intervention has been used during the AMK investigation, and a control group, in which the intervention has not been used (adult-only intervention). Participants from an ongoing prospective study on the mental health and quality of life of maltreated children after a report to an AMK, will be contacted to complete a questionnaire twice. Multivariate regression analyses will be used to determine effectiveness of the Child-Interview intervention. The economic evaluation will involve a cost-effectiveness analysis and a cost-utility analysis. Results/Discussion This will be the first study to examine the effect of AMK involvement in the Netherlands. Using the Child-Interview intervention during AMK investigation may prevent or reduce negative outcomes of child maltreatment, which may result in a lower consumption of healthcare and other services. In addition, the importance of economic evaluations is increasingly recognized, and economic evaluations about child maltreatment are scarce. Limitations include the risk of potential recall bias and selection bias. Trial registration NTR3728 , funded by ZonMw, project 15700.2012