Only a small percentage of Americans meet recommended physical activity guidelines. In an effort to increase physical activity through attending the gym, the current study evaluated how gym attendance was affected by providing incentives and daily competition to gym members. We conducted two studies with more than 100 gym members. First, we used an alternating-treatments design with two conditions: typical gym days and gym days with a physical activity competition and incentive for the winner. Gym attendance was substantially higher on days with an added competition and incentive compared to typical days. We then conducted a component analysis, using an alternating-treatments design with three conditions: typical gym days, competition without incentives, and incentives without a competition. Gym attendance was higher in both the competition without incentive and incentive without competition conditions compared to typical gym days, with the highest levels of attendance occurring in the incentive-only condition. Results of the two studies suggest that providing incentives to gym members can increase group gym attendance. Increasing gym attendance has the potential socially important implication of increasing Americans' physical activity and overall health.