The present study is an attempt to examine the relationships among university experience and psychological traits of Thai students. There are three major research objectives.First, to find out whether the students with different types and amount of university experiences would differ on the three psychological characteristics. namely, moral reasoning ability, future-orientation, and ego identity attainment. Secondly, to explore the relationship between the bio-social and background characteristics of the students and university experience. Finally, to compare the predictive powers of bio-social and background variables and university experience variables on these psychological traits. 
                In this field study, the research sample consisted of  273 third and fourth year students at Kasetsart University and Srinakharinwirot University. 
                These students were asked to respond to sets of questionnaires in a booklet while they were assemble in the university. There were 3 sets of variables being assessed. The first group consisted of 5  types of university experiences which were the number of social-behavioral oriented types of courses taken, academic achievement, extracurricular activity and desirable peer group experience. The second group consisted of moral reasoning ability, future-orientation and ego identity attainment measures. The final group consisted of 10 bio-social  and background variables. 
                Four hypotheses were tested in this study by carrying out the Analysis of Variance with three way Factorial Designs and the Multiple Regression Analysis on the data of the total sample as well as on the data of different groups of respondents, classified by the bio-social and background variables. 
                There were four major research findings in this study. First, the students who had taken more courses in social behavioral science were the ones with higher ego identity attainment than the students who took less number of these courses. In  addition, the students who took more social science courses and earned higher Academic achievement, were the ones with higher moral reasoning ability and more future-orientation. This result was more evident in the students from low socio-economic families. Secondly, the amount of desirable peer group experience and the perception of social emphasis in the courses taken were good predictors of moral reasoning ability, future-orientation and ego identity attainment among these students. Furthermore it was found that the 5 university experiences namely, number of courses taken in the areas of social-behavioral science, perception of social emphasis in the courses taken, academic achievement, extracuricular activities and desirable peer group experience together yielded higher predictive powers of the three psychological traits in female students from low socio-economic families than the other three comparative groups (Average prediction of 46% in low socio-economic females, 26% in low socio-economic males, 23% in high socio-economic males, and 31% in high socio-economic females). 
                Thirdly, it was found that two sets of variables (one consisted of the five types of university experience and another consisted of five students' background variables, namely, students' s age, both parental levels of education, student' s expense per month and working while studying) together could predict each of the three psychological characteristics of the students than anyone set alone. This result was found in the total sample and was more evident in the following 3 groups of students, i.e., the students who resided with own family, students from lower socio-economic families and students who partcipated in social volunteering activities. 
                Finally, the result showed that in the group of students from higher socio-economic families, the ones who participated higer in the university activity were higher on the moral reasoning scores than the low participants. On the other hand, the working students who participated highly in the university activity together with taking  more socially oriented courses  with good grades were the ones with high ego identity scores. However, on the whole, the amount of participation in the university' s extracurricular activities of these students did not relate highly to the psychological characteristics of the  students as previously expected. 
                The results from this study showed the importance of various types of university experience in relation to the desirable psychological characteristics of the Thai students. Furthermore, This research study has identified the various types of students who could greatly benefit from these experiences. The suggestions based on this study are three folds. First, male students, students from lower socio-economic family and students who resided with their family should be encouraged to take more courses in the areas of social behavioral sciences. Secondly, the students from the higher socio-economic family and students who participate in the nonaltruistic activities should be stimulated to perceive more strongly the social emphasis and implications of the courses they are taking. Thirdly, the orientation for better peer group experience should be given to the  following  5  types of students: male students, students from lower and also higher socio-ecomomic families, students who reside with their family, and student who participate in the nonaltruistic activities. Finally it is suggested that the universities should increase the quality of the content and the processes involved in the various university activities.