A study was conducted to determine whether a stable set of core characteristics found to be associated with creativity in samples of creative adults would also distinguish a group of professional jazz musicians selected for excellence of improvisational ability. A second purpose of the study was to see whether such differences found between groups of professional adults would also be found between similar groups of adolescent musicians. A total of 60 male professional musicians (30 jazz and 30 symphonic) and 60 male student musicians (30 jazz and 30 symphonic) were asked to respond to items of the Adjective Check List (ACL). The ACL failed to distinguish between jazz and symphonic players at every level. Findings raise questions about the generalizability of the ACL scale. (LP)