Depression, is an important psychologic disorder. So, it is of importance early diagnose (Oskay,1997). Various depression scales are used the measurement of depression. Although Zung Depression Scale, which is one of these, is used in researches especially psychiatry branch, validity and reliability studies were done only by Ceyhun and Akça in psychiatric patients. There is a need for valid and reliable tools to determine degree of depression in the young. So, validity and reliability studies are needed so that It could be used Zung Depression Scale in adolescents. This research covers a total of 1221 students, 767 “normal” university students and 212 patient university students and 242 highschool students.

“Structure and alike scale” validity methods and “depression” sub-scale of SCL-90R scale with Beck Depression Inventory were used. In determining of the reliability of scale two half validity-Cronbach Alfa Coefficient and Gutman Split-half and Spearman Brown were used. Besides, Kaiser-Meyer-Olkin Sampling Adequecy and Berlett’s Test of Sphericity analysises were administered to determine factor structure of scale then the factor analysises were done separately for highschool, university patient student groups.

In terms of depression points averages of highschool and university students, as there was no significant difference in the alpha level of p<0.05 in terms of Zung Depression Scale points between high students and university normal students group, there was a significant difference on behalf of the high students. There was significant difference on behalf of the normal students in terms of depression point averages.

Consequently, it is said that Zung Depression Scale is applicable in respect of validity and reliable for depression levels of normal and patient students in highschool and university students. In this context, it could be suggested that the scale be used as a validity and reliability means in the measurement of depression levels of normal and patient students and researches