Background: Secondary prevention involves the early detection of disease while it is asymptomatic to prevent its progression. For adults with intellectual and developmental disabilities, secondary prevention is critical as they may not have the ability to recognize the early signs and symptoms of disease or lack accessible information about these. Methods: Linked administrative health and social service data were used to document uptake related to four secondary prevention guidelines among adults with intellectual and developmental disabilities. Rates were compared to those from a general population sample representing the same age ranges. Results: Of 22% of adults with intellectual and developmental disabilities had a periodic health examination in a two-year period (compared to 26.4% of adults without intellectual and developmental disabilities). Adults with intellectual and developmental disabilities were less likely to undergo recommended age and gender-specific screening for the three types of cancer studied (colorectal, breast and cervical). Conclusions: Adults with intellectual and developmental disabilities in Ontario experience disparities in secondary prevention. As changes to primary care delivery and secondary prevention recommendations in the province and elsewhere continue to evolve, close monitoring of the impacts on adults with intellectual and developmental disabilities combined with dedicated efforts to increase access is warranted.