A study investigated factors affecting the development of positive attitudes toward environmental issues among college students, focusing on the direct and indirect effects of student background characteristics, institutional characteristics, and college experience and outcomes variables. Data were drawn from the Cooperative Institutional Research Programs's follow-up survey of the 1985 freshman class, using a subsample of the database representing 18,887 students. Analysis of these data suggests that being male or liberal increases the likelihood of positive environmental attitude development. In addition, the results suggested that the number of science courses and human ethical/social activist values play important roles in development of a positive attitude toward the environment. Also, student academic and social integration appear to indirectly influence environmental attitude development. Based on these findings, it is urged that colleges and universities find methods to support: (1) development of a science curriculum incorporating environmental issues for both science and non-science majors; (2) hiring of environmental science faculty or retraining of other science faculty; and (3) development of public forums for student and faculty discussion of social issues and human ethics. Appended materials include definitions of variables, data summaries, and analytical models. (Contains 81 references.) (MSE)