The purpose of this study is to comparechanges in attitudes of students about their study of biology in the classesthought by five biology teachers who experienced an Iowa Chautauqua workshopwith and two non-Chautauqua teachers who had no experience with anyprofessional development program. The results indicated that there aresignificant differences in student attitudes in favor with students of the fivebiology teachers who experienced of a full year of experiences an IowaChautauqua workshop.