The medical model of alcoholism has long been the accepted view of alcoholic dependence and addiction. This perspective has been the most prominent in both research and treatment. However, multidimensional models of alcoholism have more recently gained acceptance and credibility, and now frequently serve as guiding concepts in research and treatment. These notions suggest that alcoholism involves many different types rather than a single syndrome. The present descriptive study was designed to explore a multidimensional concept of alcoholism for an in-patient alcohol treatment population through the use of two different self-report personality measures, the Minnesota Multiphasic Personality Inventory (MMPI) and the Millon Clinical Multiaxial Inventory (MCMI). The results indicated that distinct and different personality types or clusters existed within this population. The five personality types found were: personality trait disturbance, borderline personality disorder, normal personality, situational disturbance, and antisocial personality. Treatment recommendations were made for each of these alcoholic types. Since members of the five groups differed widely in personality it was proposed that treatment for each group should differ. Additional recommendations for future research were also made.