As of 2012 it was estimated that there were 5.1 million Ultimate Frisbee players in the United States alone. One of the reasons offered for the increased popularity of Ultimate Frisbee is that it is fun. Given that lack of enjoyment is frequently offered as one of the reasons for physical inactivity, the fun factor' associated with Ultimate Frisbee increases the likelihood of a lifetime pursuit of physical activity. Nevertheless, to our knowledge there is no research exa ning the physiological responses to Ultimate Frisbee. Therefore, the purpose of this study was (a) to assess the cardiovascular and metabolic responses to Ultimate Frisbee and (b) to determine if Ultimate Frisbee meets current guidelines for improving and maintaining cardiorespiratory fitness.