Maltreatment can have a profound adverse effect on the health of individuals with intellectual disabilities (ID). People with ID may also be more likely to experience maltreatment than other groups. Historically, data on prevalence of maltreatment among people with ID have been sparse and methodologically weak but have suggested that the scope of the problem is considerable. Studies published between 1995 and 2005 were reviewed to determine estimated maltreatment prevalence among people with ID based on recent literature. Prevalence estimates for people with ID were compared to estimates for people with no disabilities and people with other types of disabilities. Only five studies provided maltreatment prevalence estimates for people with ID. The limited data suggest that maltreatment is more prevalent for people with ID than for people with no disabilities and may be higher for people with ID than for people with certain other disabilities. Most of the available research is still based on convenience samples. More population-level data are needed to provide reliable estimates of the prevalence of this important health problem. Key Words: maltreatment; prevalence; intellectual disability (mental retardation) M altreatment has been identified as a significant health issue for people with intellectual and other disabilities [Sobsey, 1994;Curry et al., 2001;USDHHS 2002]. Among the general population, exposure to maltreatment has been shown to produce a range of sequelae, including physical trauma, compromised psychological health, or death [Tjaden and Thoennes, 2000;Ireland, 2002]. In addition to these consequences, people with disabilities may develop secondary disabilities and/or suffer loss of independence [Mitchell and Buchele-Ash, 2000;Swedlund and Nosek, 2000]. For example, a person with an intellectual disability may develop emotional problems as a result of psychological maltreatment or develop a secondary mobility disability as a result of physical abuse.Unfortunately, while maltreatment in the general population has been recognized as a national priority with large-scale efforts to measure the prevalence of maltreatment and violence (e.g., National Child Abuse and Neglect Data System (NCANDS); National Violence Against Women Survey), little attention has been devoted to collecting comprehensive data on maltreatment of people with disabilities. Although the most recent report based on NCANDS data included disability as a demographic category, the data are acknowledged to be underestimates [USDHHS, 2005]. The data that are provided are for children with disabilities in general, with no information about specific types of disabilities.A number of authors [Jaudes and Diamond, 1985;Ammerman and Baladerian, 1993;Sobsey, 1994] have reported that individuals with disabilities are more likely to be maltreated than individuals without disabilities. Moreover, it has been asserted that individuals with intellectual disabilities (ID) are at especially high risk [Levy and Packman, 2004]. One oft-cited study [Cross et a...