The prevalence of coronary heart disease (CHD) was studied in parents and grandparents of 2,419 children surveyed for lipid levels. Children and their families were divided into 3 groups depending on the level of each lipid and lipoprotein studied in children: high greater than or equal to 95 percentile (p), medium 5-95 p, and low less than 5 p. Total cholesterol (Chol) and triglycerides (TG) were determined by enzymatic techniques in autoanalyzer. C-HDL was determined by precipitation method. C-LDL and C-VLDL were obtained by Friedewald-Fredrickson's equation. The prevalence of CHD in parents and grandparents was ascertained from clinical history. Fathers of children in the high groups of Chol, TG, C-LDL/C-HDL, and low group of C-HDL had increased prevalence of CHD compared with those of the low groups of Chol, TG, C-LDL, C-LDL/C-HDL and high group of C-HDL. The strongest association was with C-HDL. Maternal and paternal grandfathers of children in the high groups of Chol had also increased prevalence of CHD compared with those of low group of Chol. There was no association with any other variable. The association was not significant neither in mothers nor in maternal and paternal grandmothers. Childhood lipid and lipoprotein levels could identify families at elevated risk for CHD.