Genetic analyses of crosses between hypertensive rodent models and their normotensive controls were performed on 43 sets of data published between 1970-1989. In each case, the cross involved F1, F2, and both backcross generations for a "complete genetic cross." Biometrical analysis estimated genetic parameters and their standard errors associated with dominance and epistasis (interaction of alleles that are not at the same locus). The statistical significance of these parameters was determined by comparing the parameter to its standard error. A purely additive inheritance pattern was seldom found. Additive/dominance inheritance was apparent in only two models. The prevailing pattern of inheritance was one with partial dominance for alleles for normal blood pressures and epistatic interactions. Finding epistasis in so many models will have implications for the application of cosegregation and linkage analyses in hypertension research.