Three personality traits theoretically associated with effective Resident Assistants (RAs) were the focus for this study. Self-report conscientiousness, extraversion, and positive affect survey data were collected from 99 university RAs. The RAs performance data were gathered from 372 resident students. Hierarchical regression analyses supported the prediction that RA extraversion and positive affect would be associated with performance. Contrary to the prediction, RA conscientiousness was nor related to the resident student evaluations. The extraversion and positive affect findings are explained in terms of the RAs' highly interactive relationship with resident students. Similar to earlier research (e.g., Hough, in press; Tett, 1998), the conscientiousness data are examined with regard to those occupational conditions (e.g., the need fur quick decision making and flexible responses) where conscientiousness may not be strongly connected with performance. (C) 2000 Academic Press.