This study comprised 1377 first degree relatives in 575 families ascertained through a comprehensive screening of the general population from 20 to 52 years of age. Path analysis using parsimonious models gave evidence of significant biologic and environmental transmission for total cholesterol (genetic and cultural heritabilities were 0.46 and 0.05, respectively), high density lipoprotein cholesterol (0.42, 0.10), triglycerides (0.21, 0.07), and systolic (0.48, 0.04) and diastolic (0.35, 0.05) blood pressure. Compared with other studies employing the same path analytic model, heritability estimates in general were among the highest reported, except for the somewhat lower genetic component in total cholesterol and triglycerides. For the first time in a single sample from the general population, lipid and blood pressure variables were investigated applying the same methodology, and good agreement was illustrated by the result that identical parsimonious models were reached for all phenotypes, with the exception of a single additional parameter for total cholesterol. About one fourth to one half of the total phenotypic variance could be ascribed to genetic sources, whereas the contribution from shared familial environment was much smaller.