Although improvements in body image have been shown for longer-lasting resistance training, research on its short-term effects is currently lacking. The present study set out to test a hypothesized beneficial effect of a single bout of resistance training on global and specific (i.e., body fat- and muscularity-related) body image states of male exercisers. Additionally, a moderating effect of drive for muscularity was explored. In a controlled crossover study, 42 experienced weight trainers received (a) a session of resistance training; (b) a session of aerobic exercise (cycling); and (c) a session of magazine reading. Body image states were assessed before and immediately after each condition, and after 24 hr. As hypothesized, resistance training, but not cycling or reading, led to a significant increase in perceived muscularity on a silhouette measure of body image states (g = 0.31 or 3 kg). Both exercise conditions led to a significant decrease in perceived body fat (g = −0.33 or −2.5% for resistance training), but for resistance training, this only held true for men lower in drive for muscularity (g = .58, p < .01). After 24 hr, scores had returned to baseline levels. Even a single bout of resistance training yields short-term improvements in men’s body image states on both the muscularity and fat dimension, which may act as a reinforcer of exercise behavior. The present findings might foster the understanding of body-image factors that contribute to the development of excessive weight-lifting behavior.