The prevalences of lowered mood and cognitive impairment, and their combination were investigated in 1993 random subjects of five birth cohorts (at age of 65, 70, 75, 80 and 85 years). The frequency of a high Zung-score (> 45), indicating depressive symptoms, in the five age groups was 11%, 13%, 20%, 16%, and 36%, respectively. The corresponding figures for a low MMSE-score (Mini Mental State Examination < 24) were 11%, 9%, 25%, 46%, and 60%; the respective frequencies of subjects fulfilling both criteria simultaneously were 2%, 3%, 8%, 12% and 24%, respectively. Overall, about 30% of the subjects with a low MMSE-score had a high Zung-score. However, more than half of the old subjects (over 75 years) with a high Zung-score also had low MMSE-scores. The data indicate that the combination of impaired cognition and lowered mood doubles in frequency by five-year intervals after the age of 70 years in the general aged population, and that this condition is present in one of four subjects at the age of 85 years.