To explore attributions about chronically ill peers, 545 older adolescents ages 17-26 read a short vignette describing a brief social encounter with a hypothetical peer suffering from a medical condition, and then responded to a series of questionnaires to assess their perceptions of that peer. Nine measures intended to assess perceptions of ill peers were developed and empirically validated. Test-retest reliability and internal consistency was moderate to good for all measures. Component structure of the Peer Acceptance Questionnaire (PAQ), Peer Acceptance Questionnaire ?? 3rd Person (PAQ-F), and Perceived Similarity Questionnaire (PSQ) were also evaluated. Principal components analysis yielded a 2-factor structure of Openness and Egalitarianism for both the PAQ and PAQ-F. A 6-factor structure of (a) Familial/Spiritual, (b) General Health, (c) Social, (d) Behavioral, (e) Physical, and (f) Educational was suggested for the PSQ. Results indicated an interaction between illness type and behavior on acceptance ratings, such that behavior potentiated the effect of illness type on acceptance. In addition, vignette characters with contagious illnesses were rated less favorably than those with noncontagious illnesses, and vignette characters displaying typical behavior were rated more favorably than either withdrawn or aggressive vignette characters. Illness-specific knowledge, ratings of perceived similarity, and ratings of assigned blame predicted acceptance ratings, whereas illness-specific knowledge and acceptance ratings predicted ratings of assigned blame. Finally, significant differences were observed between first- and third-person ratings of both acceptance and assigned blame.