Caffeine has been shown to reduce leg-muscle pain during submaximal cycle ergometry, as well as in response to eccentric exercise. However, less is known about its analgesic properties during non-steady-state, high-intensity exercise. The primary aim of this study was to assess the effect of 2 doses of caffeine on leg pain and rating or perceived exertion during repeated bouts of high-intensity exercise. Fifteen active men completed 2 bouts of 40 repetitions of “all-out” knee extension and flexion of the dominant leg at contraction velocity equal to 180°/s. Before each trial, subjects abstained from caffeine intake and intense exercise for 48 hours. Over 3 days separated by 48 hour, subjects ingested 1 of 3 treatments (5 mg/kg or 2 mg/kg of anhydrous caffeine or placebo) in a randomized single-blind, counterbalanced, crossover design. Leg muscle pain and rates of perceived exertion were assessed during and after exercise using established categorical scales. Across all treatments, pain perception was significantly increased during exercise, as well as from Bout 1 to 2, yet there was no effect of caffeine on pain perception or rates of perceived exertion. Various measures of muscle function were improved with a 5 mg/kg caffeine dose vs. the other treatments. In the 5 -mg/kg trial, it is plausible that subjects were able to perform better with similar levels of pain perception and exertion’.