Studies have shown that expectations about exercise outcomes are associated with exercise behavior. Outcome expectations can be assessed by self-report questionnaires, but a new method-the expectancy accessibility task-may convey unique information about outcome expectations that is less subject to respondent biases. This method involves measuring the reaction time to endorse or reject an outcome We examined the relationship of self-reported outcome expectations and expectancy accessibility tasks in a pilot study of sedentary endometrial cancer survivors (N = 20). After measuring outcome expectations and expectancy accessibility, participants were given an exercise program and asked to monitor exercise for 7 days using diaries and accelerometers. Analyses revealed no relationship between outcome expectation scores and exercise, but shorter response times to endorse positive exercise outcomes was related to more exercise in the next week (p = .02).