A systematic review of the prevalence rates of chronic health conditions in populations of children with intellectual disability was provided. We identified 2,994 relevant studies by searching Medline, Cinahl, and PsycINFO databases from 1996 to 2008. We included the 31 studies that had sufficient methodological quality. The 6 most prevalent chronic health conditions in children with intellectual disability were epilepsy (22.0/100), cerebral palsy (19.8/100), any anxiety disorder (17.1/100), oppositional defiant disorder (12.4/100), Down syndrome (11.0/100), and autistic disorder (10.1/100). The reported prevalence rates of chronic health conditions in this population was much higher than in the general population. However, both the number of studies that were included and the number of chronic health conditions they reported about were limited. There is an urgent need for better evidence on the prevalence of chronic health conditions among children with intellectual disability.