Social-psychological data were gathered by questionnaires and the Omnibus Personality Inventory on two entering freshmen classes. A follow-up survey two years later, of students who had withdrawn, determined reasons for withdrawal and the nature of the problems these students experienced while still in attendance. Data suggested that salient environmental characteristics of the institution (large, liberal, affluent, secular, academically competitive, and cosmopolitan) were related to attrition, and the relationship differed according to sex. Male student drop-outs tended to be more religious or politically conservative. Female student drop-outs tended to be less esthetically inclined, to come from less wealthy homes, to consider themselves less attractive, and to have lower verbal aptitude scores. Both sexes, from smaller communities and with lower mathematical aptitudes, tended to drop out. Various university presses, then appear related to student behavior, with the same environmental press having different effects depending on the sex and social-psychological characteristics of the student. (KP)