Introduction: There is considerable international research indicating health disparities between people with and without intellectual disabilities. It is important that comparative studies use representative population samples. This study compares a total administrative population of adults with intellectual disability to a random stratified general population sample. Methods: An administrative population of 217 adults with intellectual disability and a random stratified sample of 2,350 adults without intellectual disability participated. A questionnaire using the International Classification of Diseases (ICD-10) Chapter Headings was administered to all participants to enable a like-for-like comparison. Findings: Unadjusted comparisons identified that adults with intellectual disability have a greater prevalence of health problems. These problems start early in adulthood and continue throughout life. However, they were less likely to experience cancers and musculoskeletal diseases. Conclusions: These findings are consistent with the hypothesis that adults with intellectual disabilities have greater prevalence rates of health problems than the general population.