In order to have a complete understanding of the relationship between physical activity (PA) and health, it is essential to be able to accurately assess PA in free-living situations. The purpose of this study was to use three accelerometers located on the dominant ankle, hip, and wrist and a heart rate (HR) monitor to estimate energy expenditure (EE) compared to measured EE while completing activities of daily living (ADL). The regression equation developed showed a significant relationship (P < 0.05) with EE. Together, HR and the hip-worn accelerometer explained 73.4% of the variance in EE with HR accounting for 59.3% (P < 0.05). Type of activity, the wrist-, and ankle-worn accelerometer each explained an additional 5%, 3% and 3% of the variance in EE, respectively (P < 0.05). The regression equation developed is a good predictor of EE during selected ADL, and allows researchers to more accurately quantify free-living PA. / School of Physical Education, Sport, and Exercise Science