"Data Trends" reports present summaries of research on mental health services for children and adolescents and their families. The article summarized in this "Data Trends" presents the results of a study of 40,636 children entering the Illinois domestic violence service system over a five-year period. The results of this study of more than forty thousand children entering a domestic violence program indicate that many children exposed to domestic violence experience problems that require mental health services. The authors note the limitations of these data and the need for the use of standardized age-appropriate instruments in future research. An important question not addressed in this research is differences in outcomes for children who experience domestic violence directly or indirectly. The study also found that just over one third (38.5%) of children were identified as not having problems in the domains assessed. Further research is required to advance understanding of the impact of domestic violence on children's mental health including protective factors, and treatment needs and outcomes. The intake data collected in the context of a crisis may not be reliable, and thus there is a need for longitudinal assessment of families and their needs, as well as control group data. Nevertheless it is evident that many families entering domestic violence programs need a range of services. The authors conclude that domestic violence programs should be coordinated with mental health agencies and other providers, with increased attention to children's needs. [This "Data Trends" presents a summary of: Lundy, M. & Grossman, S. F. (2005). The mental health and service needs of young children exposed to domestic violence: Supportive data. "Families in Society: The Journal of Contemporary Social Services," 86(1), 17-29.]