Effects of neuroticism and social comparison orientation on social comparison among cancer patients were examined. A computer program that enabled patients to access information about fellow patients' disease-related experiences was developed. Patients selected more interviews concerning more as compared to less fortunate others, spent more time reading, and showed more favorable reactions to such information. Individuals with a strong comparison orientation in particular tended to engage in and to respond to social comparison. Neuroticism was associated with higher interest in social comparison and with less favorable reactions, regardless of its direction. High-neurotic individuals reacted more positively to upward than to downward comparisons, whereas the reactions of low-neurotic individuals were unaffected by comparison direction. The latter effect was replicated using a general affect measure, but solely among individuals with a strong comparison orientation.