The present research is a comparative study on some of the psychological characteristics of students in different colleges and departments of Shahid Beheshti University. The hypothesis being that there are correlations between students educational achievement, self-esteem, psychological health, and cognitive factors, with factors such as educational level, sex, employment, whether the field of study is applied or not, and the students expectations of their field of study. Participants were 1185 students who were selected using systematic sampling. The instruments used were as follows: a personal demographic questionnaire, an attitude questionnaire, an IQ test, a personality test, and a test of self-esteem. The results were analyzed using one way ANOVA Cochran's tests, Kruskall- Wallis ANOVA, t-test for independent samples and multifactorial regression analysis. The outcome showed that students who were studying at post graduate level, employed students and, those who were living with their families, enjoyed higher self- esteem and better psychological health. These results are consistent with and confirm previous research in the filed.