In an experimental study neuroticism was examined as a moderator of breast cancer patients' affective reactions to social comparison information about a fellow patient. Fifty-seven women with breast cancer completed Eysenck's Personality Questionnaire and received social comparison information about a fellow patient who was either doing better (upward condition) or worse (downward condition) than themselves. As expected, patients showed more positive reactions to upward comparison information than to downward comparison information. Moreover, neuroticism was related to responding more negatively and less positively to social comparison information. Although respondents high and low in neuroticism did not differ in their reactions to downward comparison information, low neuroticism was associated with more positive responding to upward comparison information.