Participants in the Affective Disorders component of Genetic Analysis Workshop 5 had access to five distributed data sets: 1) 187 families from the Collaborative Depression Study, 2) 202 families ascertained as part of the NIMH Family Studies on Affective Disorders, 3) a compilation of 46 pedigrees informative for X-linked markers, 4) HLA typing on 116 kindreds from the Toronto-Rochester Depression Study, and 5) 81 members of an Old Order Amish pedigree demonstrating linkage to markers on chromosome 11p. These databases are each summarized after a brief account is given of the genetics of the affective disorders and commonly used diagnoses. The emphasis of the Workshop was methodologic, with contributions divided evenly between linkage and nonlinkage applications. Contributions are summarized under four substantive areas: regressive logistic models, segregation and other familial analyses, methodologic considerations in linkage analysis, and the relationship between HLA and affective disorders.