In previous pesticide residue surveys of the United States population, residues of p,p'-DDT and p,p'-DDE have been shown to be higher in blacks than in whites. The role of social class factors in this difference is explored in this paper. In a population survey of 800 residents of Dade County, Classified by the Hollingshead Two Factor Index, serum levels of DDT and DDE were significantly lower in the more affluent Social Classes I and II than they were in the less affluent Social Classes IV and V in both races. Within these social classes, blacks still had higher residues. Residues were greater in the less affluent whether classified by the Hollingshead Two Factor Index, census tract population density or median income of the census tract. Significant correlations of DDT and DDE were also observed in the first two decades of life--the approximate DDT age of society. The epidemiologic and public health consequences of these findings, reflective of a tropical clime, are discussed and the role of the domestic environment and the implication for global monitoring studies reviewed.