Aim Depression is the most common psychiatric disorder and the second most common cause of disability among older adults. The objective of the present study was to investigate the prevalence of depression and related social and physical factors in the Iranian elderly population in 2012. Methods In this cross‐sectional study, 1350 Iranian older adults aged older than 60 years were selected considering the gender proportion of the population of five out of 31 provinces of Iran. To define depression, the short form (15‐item) of the Geriatric Depression Scale was administered. To analyze the data, logistic regression was carried out using stata software (version 12.0). Results From 1350 participants, 642 (47.5%) were men and the rest were women. The mean ± SD age of the sample was 69 ± 7 years. The prevalence of depression was 36.7% (42.5% in women and 30.2% in men). At the bivariate level, sex, educational level, marital status, satisfaction with income, occupation, relationship with the financial provider, leisure time, activities of daily living, and frequency of meeting with friends and relatives were factors determining the odds of depression. However, after multivariate control, marital status and educational level were removed from the final model. In contrast, smoking, which was insignificant at the bivariate level, became significant at the multivariate level. Conclusions Depression has a high prevalence among the Iranian elderly population. Therefore, it is important that this vulnerable group is provided with access to supportive environments that involve active participation in occupational and social activities, which in turn help reduce the chance of suffering from depression. Geriatr Gerontol Int 2017; 17: 126–131.