Genetic factors explain a non-negligible part of the vulnerability to alcohol dependence, the genetic influence in males being estimated at around 60%. The search for gene(s) potentially implicated in alcoholism is counteracted by the clinical heterogeneity of alcoholism, but also by heterogeneity of the etiologic factors involved. It is thus necessary to redefine more specific phenotypes with more simple determinism, and to focus on more specific subsets of candidate genes. In this view, the existence of co-occurrence (presence at the same time, whatever the cause) between antisocial personality and alcoholism is frequently reported. Three hypotheses have been previously proposed to explain this co-occurrence. Firstly, it could be a pure artefact or contamination, due to common items in diagnostic manuals widely used, such as the DSM or ICD. Secondly, antisocial personality and alcoholism could share common etiologic factor(s), and determine a 'real' co-morbidity. Finally, common genetic factors between these two disorders may exist, with the observation of a co-transmission of both disorders more often than expected by chance alone, meaning the existence of co-aggregation. Each of these three hypotheses will be reviewed and discussed.