Background: Our research team aimed at determining the prevalence of depression and mutual interaction of other diseases among elderly in today’s changing period of morbidity of population due to social and economic transition.Goal: To determine the correlation between depression and other diseases among elderlyObjectives:1. To determine the prevalence of depression among elderly2. To find out the correlation between depression and other diseasesMaterials and method: The research was carried out by cross sectional method. In the research was involved 1207 elderly, who are retired, of which 60 and over for male and 55 and over for female from one cluster of each economic and geographic regions of Mongolia. The depression was evaluated by using Geriatric Depression Scale.Results: In the research was involved 392 (32.5 percent) men, 675 (67.5 percent) women and their mean age was 68.1±8.1 (68.9±6.5 in male and 65.7±8.5 in female) from 4 economic and geographic regions of Mongolia. Among survey involved elderly, 16.5 (199) percent of them were found to have depression. Out of survey involved depressed elderly, 27.6 percent were male and 72.3 percent female. The mean age of depressed elderly was 67.9, in which 67.1 in women and 70.2 in men. Due to depression status among survey involved elderly, the share of elderly, who inclined to affect by depression was 158 (13.1%). Furthermore, 169 (14%) of them were affected by slight depression, while 30 (2.5%) of them were with severe depression.Among survey involved elderly, 24.5 percent of elderly with anxiety were inclined to be affected by depression and 29.2 percent of them were with mildly depression. However, 5.6 percent of elderly with severely level of anxiety were affected by severe depression. It was not found severe depressed elderly among elderly, who did not have anxiety. The depression of elderly and their morbidity has direct correlation. Elderly depression and anxiety has direct medium correlation.Conclusions:1. The prevalence of depression among Mongolian elderly refers 16.5 percent.2. Depression among Mongolian elderly has direct correlation to some investigated somatic diseases.