This study of suicide notes, concerning the demographic variables of age and sex, involved the deduction of 50 classifications (protocol sentences) that reflected important aspects of Shneidman's formulations with regard to suicide. Independent judges noted the incidence of contents corresponding to the protocol sentences in the notes left by 60 suicides-20 notes written by individuals (females and males) in each of the three categories of Young, Middle, and Late Adulthood. Age (notably in regard to Young Adults), but not sex, was found to be a critical discriminating variable on a number of specific classifications and clusters of these classifications (Perturbation, Relations, Cognitions Regarding Self, and Long-Term Instability), although considerable similarities were also noted across the adult life span. Implications of the results are discussed.