OBJECTIVE: This study compared three methods for identifying type 1 and type 2 alcoholism to determine how well the methods agree. It also evaluated the comparability of each of these schemes to the primary/secondary approach to subgrouping alcoholics. METHOD: Fifty male alcoholic inpatients were given diagnoses of primary alcoholism without antisocial personality disorder or primary antisocial personality disorder with secondary alcoholism on the basis of data from structured interviews. Operationalized criteria for type 1 and type 2 alcoholism from three groups of researchers (Gilligan et al., von Knorring et al., and Sullivan et al.) were also used to designate subgroups of the same subjects. RESULTS: Subgroups of subjects classified as having type 1 or type 2 alcoholism according to the criteria of von Knorring et al. and of Sullivan et al. showed good levels of agreement, but the criteria of Gilligan et al. yielded poor agreement with those of the other two schemes. Subgroups with type 1 or type 2 alcoholism according to the criteria of Sullivan et al. showed significant overlap with subgroups diagnosed according to the primary/secondary alcoholism scheme: there was 73% concordance between the type 1 subgroup and the subgroup with primary alcoholism and 73% concordance between the type 2 subgroup and the subgroup with primary antisocial personality disorder and secondary alcoholism. CONCLUSIONS: There is variability in assigning diagnoses of type 1 and type 2 alcoholism with the use of current methods. Also, type 1/type 2 classifications based primarily on age-at-onset factors significantly overlap with the primary/secondary classifications of alcoholics.