The purpose of this study was to provide baseline data for revising the recommended energy intake for Korean adults. We recruited 290 adults so as to determine their resting energy expenditure (REE) and energy intake. The REE was measured by indirect calorimetry. We also calculated the REE from prediction equations formulated by World Health Organization (WHO). The energy intake for two consecutive days was assessed using the 24 hour recall method. The body weight, lean body mass (LBM) and percentage body fat were measured using the INBODY 3.0 system. We compared the results of three age groups; 20 to 29 years, 30 to 49 years and 50 years or more. The average energy intake of each age group was below the 7th Korean Recommended Dietary Allowances (RDA). The average energy intake was lower in the older age groups. However, no difference was observed among the age groups when the energy intake as a percentage of the Korean RDA was compared. Our measurement of the REE was higher than the REE calculated by the WHO's method. Correlation coefficients between the measured and the calculated values of REE for all age groups showed significant correlations (r = 0.475-0.672). As the ages of all the subjects increased, the REE/kg of body weight decreased. There were no significant differences in the REE / kg of the LBM between the different age groups; however, the REE/kg of the LBM was higher in the female group than in the male group. Negative correlations of the REE with the age (r = -0.242) and body fat ratio (r = -0.313) were observed; positive correlations of the REE with the BMI (r = 0.265), height (r = 0.570), weight (r = 0.562) and LBM (r = 0.586) were also found (p < 0.01).