The purpose of this study was to determine if a 7-hour "Project Learning Tree" (PLT) workshop had a positive effect on pre-service teachers' attitudes toward teaching environmental education. The subjects of the study were 140 pre-service teachers enrolled in an elementary science education course in Pennsylvania. Attitude was measured using the "Environmental Education Attitude Scale" developed for the purpose of this project. The findings of the study include: (1) pre-service teachers showed a significant positive change in attitude score toward environmental education after participating in the 7-hour PLT workshop; and (2) pre-service teachers showed significant positive changes in their mean attitude score on three of the four subcomponents of the scale. The cumulative score on the subcomponent scales for comfort/discomfort, need, and equipment/technology showed positive changes. The cumulative score on the time subcomponent did not show a positive change in attitude. (KR)