The purpose of this study was to examine total energy expenditure (TEE) in Japanese men under free-living conditions using various field methods, and compare these methods with the doubly labeled water method (DLW) . Ten Japanese men, aged 24.2±1.8 (mean±SD) yrs, were studied for 14 consecutive days. TEE was assessed by DLW, activity record method (AR ; using relative metabolic rate and calculated basal metabolic rate), heart rate monitoring methods (Two-line and FLEX-HR methods), and accelerometer method (AC) . Energy intake (EI) was also evaluated over the same period. Although TEE estimated by AR (2730±139 kcal⋅day^-1), Two-line (2925±433 kcal⋅day^-1), and FLEX-HR (2949±506 kcal⋅day^-1) did not differ significantly from the TEE determined by DLW (2910±524 kcal⋅day^-1), there was no significant relationship between each of these methods and DLW. In addition, El (2963±482 kcal⋅day^-1) and TEE determined by DLW were similar, and there was a significant correlation (r=0.809, P<0.01) . Compared with DLW, AC (2697±541 kcal⋅day^-1) underestimated TEE at the group level ; however, AC was the only method to show a significant correlation with DLW (r=0.871, P<0.001) . Therefore, it seems possible that AC would accurately estimate TEE at the individual level by improving both the instrument and its methodology.