A whole genome scan has been conducted on 105 families ascertained for probands with a diagnosis of alcoholism by the Collaborative Study on the Genetics of Alcoholism (COGA). To identify chromosomal regions likely to contain genes contributing to the development of this disorder, data from 296 highly polymorphic markers have been analyzed using the MAPMAKER/SIBS [Kruglyak and Lander, 1995] and GENEHUNTER-PLUS [Kruglyak et al., 1996; Kong and Cox, 1997] multipoint linkage programs. Chromosome 6 exhibited lod scores greater than 3.0 and was further tested by two-point linkage analyses at each marker along the chromosome to assess the consistency of results from these allele sharing linkage programs. Two-point linkage was assessed with MAPMAKER/SIBS, GENEHUNTER-PLUS and the SIBPAL subprogram of the SAGE package of genetic epidemiology programs [Elston, 1997].