The purpose of this investigation was to examine the relationship between exercise adherence and the combined effects of locus of control and attitudes toward physical activity. The primary instruments used were the Internal, Powerful Others, and Chance Scales (Levenson, 1974); the Exercise Objectives Locus of Control Scales (developed by the first author); and the Revised Children's Attitudes Toward Physical Activity Inventory (Schutz, Smell, & Wood, 1981a). The subjects were 61 females, ages 15-57 (M = 28), voluntarily participating in 8- to 12-week aerobic fitness programs. Findings indicated only a weak relationship between adherence and the combination of locus of control and attitudes. Results of stepwise regression analysis revealed that two attitude measures were the best predictors of exercise adherence. In general, those subjects who at the outset of the programs had a less positive attitude toward participating in physical activity for continuing social relations and a more positive attitude toward participating in order to reduce stress and tension tended to have a higher percent attendance.