The effect of environmental instruction on students` environmental attitudes was studied in two environmental classes and one business class of university undergraduates. Changes in students` environmental attitudes were assessed from a questionnaire survey administered before and after exposure to a 16 week course. The results indicated statistically significant differences in students` attitudes toward the environment between the pretest and the posttest. The two environmental classes had the positive effect and the students exhibited more environmentally favorable attitudes. Accordingly, this study confirmed the positive effect of environmental instruction on attitudes toward the environment at a university level.