There is a widespread belief that positive thinking is a key strategy to cope with cancer. While dispositional optimism is associated with lower psychological distress, the literature supporting the efficacy of cognitive-behavioral therapy indirectly suggests that realistic thinking is also effective. This article describes the development of the Thoughts and Anticipations about Cancer questionnaire designed to directly compare the effect of realistic thinking versus positive thinking on adjustment to cancer. Preliminary data on its relationships with psychological distress gathered in 10 breast cancer patients are promising. The validity of the Thoughts and Anticipations about Cancer questionnaire will need to be confirmed in larger studies.