The purpose of this investigation was to determine the effect of a single bout of strenuous resistance exercise on resting metabolic rate (RMR) in resistance-trained (RT) and untrained (UT) subjects. Ratings of perceived muscle soreness (RPMS) and creatine kinase (CK) activity were measured to examine the relationship between muscle damage and RMR. All variables were measured on four consecutive mornings in ten RT and ten UT healthy male subjects. After a baseline measurement, each subject performed a weight lifting exercise comprised of 3 sets of 12 repetitions at 70% of one repetition maximum (1-RM) for 8 different lifts. RMRs were measured on three consecutive days following the single bout of resistance exercise. As a result, RMR was significantly elevated for UT subjects when measured at 12h post-exercise, whereas RT subjects did not show significant elevation in RMR. RMR measured at 36h post-exercise was still elevated although results did not show significance. CK for UT subjects were significantly elevated for up to 36h and remained elevated for up to 60h post-exercise. RPMS for UT subjects were also significantly elevated for up to 60h post-exercise. RT subjects did not show significant elevations in these variables following the exercise bout. It is concluded that muscle damage caused from the bout of resistance exercise may partially contribute to elevations in post-exercise RMR. Keyword(s): exercise/fitness