Unlike the aging population without intellectual and developmental disabilities (IDD), few standardized performance measures exist to assess physical function and risk for adverse outcomes such as nonfatal, unintentional injuries. We modified 3 selected standardized performance tools in the areas of general fitness (2-Minute Walk Test), balance and gait (Performance-Oriented Mobility Assessment I), and functional independence (Modified Barthel Index) for administration with people with IDD. The modified tools were piloted with 30 participants. Results indicated the measures are strongly associated and successfully distinguished between participants with an adverse health event in the previous year. The modified tools have potential to provide clinicians with quantitative measures that track physical performance changes associated with aging in people with IDD.