AbstractA commingling analysis of the distribution of systolic and diastolic blood pressure was performed on measurements from 9,226 individuals living in Tecumseh, Michigan during 1962–1965. Even after correcting for skewness in the distributions, multiple normal distributions fit the data significantly better than a single normal one, suggesting some level of commingling. The exact nature of the components differed depending on the phenotype, and the number of components entertained, suggesting a possibly complex etiology, but with some definite qualitative effects. Segregation analysis under the mixed model is needed to address the nature of blood pressure in this community more definitivel