Age and sex effects on 3H-imipramine platelet binding sites were determined in 58 normal subjects (27 males, 31 females). The correlation of age with either the maximal imipramine binding (Bmax) or the dissociation constant (Kd) was statistically nonsignificant in both males and females. Males did not differ from females in Bmax and Kd values. The implications for psychiatric research were discussed.