Behavioral contracting was used to encourage physical exercise among college students in a multiple‐baseline design. Subjects deposited items of personal value with the experimenters, which they could earn back on fulfillment of two types of contract contingencies. Subjects selected weekly aerobic point criteria, which they could fulfill by exercising in the presence of other subjects. In addition, subjects contracted to observe and record the exercise of other subjects and to perform an independent reliability observation once each week, with both of these activities monitored by the experimenters. Results indicated that the contract contingencies produced increases in the number of aerobic points earned per week for seven of eight subjects, that the aerobic point system possesses several advantages as a dependent variable for behavioral research on exercise, and that inexperienced observers could be quickly trained to observe exercise behavior and to translate those observations into their aerobic point equivalents. Finally, in a followup questionnaire completed 12 months after the end of the study, seven of the eight subjects reported that they were earning more aerobic points per week than had been the case during the baseline condition of this experimen