Aims: The purpose of the present study was to compare alcoholic subtypes (type 1 versus type 2) with regard to platelet monoamine oxidase (MAO) activity. A possible relationship between enzyme activity, personality traits and executive functions was also investigated. Methods: Seventeen type 1 and 16 type 2 in-patient male chronic alcoholic patients and 17 healthy male volunteers were included in the study. The personality traits were investigated by the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). Executive functions were assessed by the Wisconsin Card Sorting Test (WCST). Results: When compared to the healthy subjects, platelet MAO activity was reduced in both alcoholic groups. The enzyme activity of the type 2 group was significantly lower than that of type 1 patients. Both groups of alcoholic patients also displayed impairment in executive functions. The comparison of the MMPI-2 scores of the study groups revealed that type 2 alcoholics had more severe psychopathology. Conclusions: The results support previous evidence suggesting that platelet MAO activity is a useful biochemical measure for the subtyping of alcoholics.