Today, about 10% of the world population are older than 65 and even it is about 30% in some of society. According to growing of population in the word and in Iran and also high prevalence of psychiatric disorders in this group, demographic and epidemiological studies are necessary.

From 1422 subjects 59 years or older, who were live in Ekbatan district of Tehran, 313 subjects were chosen randomly. Finally 204 subjects were enrolled and completed the questionnaires of GDS-15, GHQ and CES-D. from study sample, 104 subjects were selected randomly and interviewed by CIDI to validate psychiatric disorders.

According to our study, 53.4% of subjects were women and 46.6% of them were male and 63% of the population were between 60-75. the life time prevalence for all psychiatric disorders were 35% and the period prevalence were 17.5%. 25.2% of subjects had only one psychiatric disorder and 6.8% and 2.9% of them had two and three or more psychiatric disorders, respectively. the most prevalence of psychiatric disorders were Major depressive disorder, Dysthymic disorder, OCD and PTSD, respectively. Some subjects had not engaged in treatment.

The results of this study revealed that the psychiatric disorders in Iranian geriatric population are common. It seems that these results can be helpful for mental health services.