Quantitative autoradiographic analysis of serotonin 5-HT1A receptors in the human brain, using [3H]8-OH-DPAT as a ligand, reveals region-specific decreases in receptor labeling with age in several cortical and hippocampal regions and in the raphe nuclei. This is due to a change in receptor density (Bmax) with no apparent change in affinity (Kd) as affirmed by saturation binding analysis on representative cortical regions. The presence of alcohol is associated with decreased binding in several cortical gyri. Suicide, gender and postmortem delay had no effect on 8-OH-DPAT binding.