The aims of this study were to (1) determine the energy expenditure of adults with and without intellectual disabilities during common activities of daily living (ADL), (2) use these values to evaluate the accuracy of equivalent activity values reported in the Compendium of Physical Activities (CPA), and (3) identify ADL that may confer a health benefit for adults with intellectual disabilities when undertaken regularly. Energy expenditure was measured for adults with intellectual disabilities (N = 31; 29.0 plus or minus 8.6 yr) and adults without intellectual disabilities (N = 15; 30.4 plus or minus 9.6 yr) while undertaking each of seven ADL: sitting quietly (SitQ); sitting watching television (SitTV); sitting and standing while completing an assembly task (SitAT, StaAT); and walking at a slow (WalkS, 3.0 km h[superscript -1]), quick (WalkQ, 6.0 km h[superscript -1]) and fast (WalkF, 9.0 km h[superscript -1]) speed, under laboratory conditions. Adults with intellectual disabilities were found to expend significantly more energy than adults without intellectual disabilities for SitQ, WalkS, WalkQ and WalkF (p less than 0.05). Energy expended by both populations was significantly more than CPA values for SitQ, SitTV, SitAT, WalkS, and WalkQ (p less than 0.02) and significantly less for WalkF (p less than 0.01). Walking at the speed of 3.0 km h[superscript -1] (50 m min[superscript -1]) was found to be sufficient to achieve moderate-intensity energy expenditure, surpassing the intensity threshold for conferring a health benefit. Energy expenditure inaccuracies of the CPA have important consequences when estimating prevalence of engagement in health enhancing physical activities among population sub-groups. The identification of slow walking as a moderate-intensity physical activity offers significant health promotion opportunities for adults with intellectual disabilities through active transport and leisure. (Contains 5 tables.)