Carbon monoxide (CO) released from the exhaust of ice resurfacing machinery is frequently found in indoor ice skating rinks. We conducted a study with 14 male adult non-smokers unexposed occupationally, who played hockey games in 4 different atmospheric CO concentrations. To document absorption, we measured their alveolar CO (alvCO). Exposure was the average CO level in the rink during the game. Environmental concentrations were between 0.0 (undetected) and 76.2 parts per million (ppm). The exposure-absorption relationship was linear (regression parameters: r2 = 0.93, slope = 0.411, intercept = -1.45). This means that for each 10 ppm of CO in the indoor air, the players absorbed enough CO to raise their alvCO by 4.1 ppm (approximately 0.76% carboxyhemoglobin). Taking into account the duration of the games, the regression coefficients were almost similar to those of an earlier study we made with 122 adult male hockey players playing in recreational leagues of the Quebec city area. These results show the exposure-absorption relationship for an acute 60-minute exposure, in a design which eliminated certain of the uncontrolled variables of our first study. It also emphasizes the importance of prevention for CO pollution in indoor skating rinks.