The study was divided into two parts, the analysis of the methodologies and the application of the methodologies in the genetic analysis of hypertension. In the first part of the study, the power, robustness, and validity of three genetic models of segregation and linkage analysis were considered: the transmission probability model; the mixed model; and the unified model which was also a mixed model with the single locus component parameterized in terms of transmission probabilities. The methods of segregation and linkage analysis found to be most satisfactory were then applied to the analysis of data on five large pedigrees in collaboration with Wright State University and to the analysis of ten large pedigrees ascertained as part of the Bogalusa Heart Study. A determination was made of the effects of partitioning large families into nuclear families and performing segregation and linkage on these nuclear families.