Depression is the most frequent cause of emotional suffering on late life. The purpose of the present study was to estimate the prevalence of depression and to assess possible under-diagnosis of depressive symptoms in the elderly. A cross-sectional study was conducted among the members of the open day care centers for older people in the municipality of Pella, North Greece. A questionnaire was developed to collect basic demographic data, including three questions from the "European Health Interview Survey", regarding self-reported and/or by a physician diagnosed depression. Moreover, to all participants the Greek validated version of the Geriatric Depression Scale (GDS-15) was applied, to screen for depressive symptoms. A total of 241 individuals took part in the study. According to the GDS, 34.9% of the participants revealed having depressive symptoms, 27.5% moderate and 7.5% severe. Having ever been affected with chronic depression reported 30.4%, of them 68.4% had been diagnosed by a medical doctor and 20.8% had received medication. Of the 160 subjects who reported never been affected by a depression, 26.9% and 3.8% screened positive for moderate and severe depressive symptoms, respectively. In seven individuals who reported not to know if they have/had depression, depressive symptoms were observed in 85.7% applying the GDS-15. Depression in the elderly in North-Greece show a high prevalence and appears to be an under-diagnosed disease. The application of GDS-15 by general practitioners would increase their ability to detect and treat depression.