this study examined the effect of aerobic exercise, health locus of control, and health value on smoking behavior. thirty-eight subjects were randomly assigned to either an exercise treatment group or a selfmonitoring control group. they were administered the hlc scale and a measure of health value and were instructed to use self-monitoring procedures in order to establish a smoking and exercise baseline. after the seven-day baseline was completed, the subjects in the exercise group continued to self-monitor. they also began an exercise program of steadily increasing aerobic exercise. subjects in the control group simply continued to monitor their smoking and exercise as they did during the baseline. following the program, the pretest measures were readministered with the stai and bdi added to the battery. results indicated that the exercise group smoked significantly fewer cigarettes than the control group. no differences were found between the exercise and control groups' hlc scores, health value scores, depression scores, or state anxiety scores. however, a difference in trait anxiety scores did approach significance. these results suggest that there may be some utility in including aerobic exercise in smoking treatment programs. possibilities for future research are discussed.