The relationship of race, sex, religion, college, and socio-economic factors to modifications in attitudes of three consecutive Cornell University Medical College classes was investigated. Results indicated that: (1) background factors are more important in attitude changes toward self than toward environment; (2) students with lower socio-economic backgrounds experience the most extensive changes in attitudes; (3) students from private colleges are more disillusioned by medical school than are those from other college categories; (4) Black students are more prone than white ones to develop conservative attitudes; (5) women develop more career ambivalence and status problems than do men; and (6) the freshman year shows most changes in attitudes. (Author)