5-HT1A, 5-HT1D, 5-HT2 binding sites and affinity and 5-HT uptake sites were simultaneously determined in frontal cortex samples from 23 control subjects, aged 16-75 years. A significant reduction in the number of 5-HT1D and 5-HT2 binding sites was found with regard to age, together with a significant decrease in the 5-HT2 binding affinity. It is suggested that the total 5-HT1 age-related loss described in previous studies could be ascribed to the 5-HT2 subtype. Furthermore, aging does not seem to be associated with a reduced cortical serotonergic innervation, as indicated by the stability of the [3H]paroxetine-labeled 5-HT uptake sites.