Despite a strong tradition of research and practical applications involving perceptions of psychosocial environment in elementary and secondary science classes, surprisingly little analogous work has been conducted at the tertiary level. Consequently, in order to facilitate such work, a new instrument called the College and University Classroom Environment Inventory (CUCEI) was developed to assess students' or teachers' perceptions of several dimensions of the actual or preferred environment (for example, personalization, involvement, task orientation, individualization) of small university or college classes often referred to as seminars or tutorials. Validation data collected from a total sample of 499 students and 20 instructors supported each scale's internal consistency, reliability and discriminant validity. Potentially useful applications of the instrument for research purposes and for improving teaching in higher education are considered. (A copy of CUCEI is included in an appendix.) (Author/JN)