Resting energy expenditure (REE) represents the amount of calories required by the body to maintain vital bodyfunctions. One of the most commonly used methods for estimating REE is indirect calorimetry. Recent studies ondifferent populations have validated a highly innovative instrument, the SenseWear® Armband (SWA), which evaluatestotal energy expenditure and, when used in resting conditions, could also evaluate REE. The purpose of this study wasto determine the agreement of the SWA in assessing REE in obese subjects and, see how this agreement varies withdifferent obesity degree.89 obese subjects (59 women and 30 men), with an age range from 35-65 years and body mass index (BMI)34.5 4.5 kg/m2 were studied. REE was measured by IC Sensor Medics Vmax (SM-29N) and by SWA. Fat mass(FM) and fat-free mass (FFM) was determined by anthropometry and bio-impedance measurements. No statisticaldifference was found between REE measured by SWA (1693±276) and REE measured by SM-29N (1627±293). Thetwo methods showed similar assessments (r=0.8, p 35 kg/m2), the agreement decreases (r =0.6 p 35