Background: Depression is one of the mental disorders which have become a public health problem throughout of the world. The objective of this study was to investigate depression and to determine its correlated factors among students at Shiraz University of Medical Sciences (SUMS).Methods: 358 students of SUMS participated in this crosssectional study in 2012. The participants were selected by Proportion Partition sampling method. A two-part questionnaire was used as the data collecting tool. In the first part, demographic characteristics and in the second part the Beck Depression Inventory (BDI) were included.Results: Mean score of depression in the studied population was 10.98. More than half of all the participants (54.7%) were symptomless; 41% of them were in the weak to moderate depression categories, and 4.2% in the strong and very strong categories. The data showed a significant relationship between scores of depression and marital status, academic grade, field content of study, use of psychoactive drugs, job outlook, problem with marriage and religious commitments. The depression scores in the married, religious and postgraduate participants and in those participants with course pleasure and excellent career perspective were lower than those in the other groups.Conclusion: Taking measures to reduce the factors leading to mental disorders is recommended. The involvement of students in socio-cultural, recreational and sport activities, reinforcement of consultation and clinical psychological services, and promotion of religious beliefs are instrumental in the enhancement of moral values and amelioration of depression among university students.