A positive family history of premature cardiovascular disease is recognized as an independent predictor of risk for cardiovascular death in first degree relatives. It is of great interest whether the progeny of families with manifest coronary heart disease can be discriminated from children with a negative family history. Therefore, we examined serum lipids, lipo- and apolipoproteins in 338 offspring whose fathers and/or mothers had been affected with a myocardial infarction before the age of 55, in comparison with 448 age- and sex-matched, healthy controls. Statistical analyses revealed marked differences between the two groups: In both age groups only high-density lipoprotein cholesterol (HDL-C), as a single parameter, and the ratios of total cholesterol (TC)/HDL-C, as well as low-density lipoprotein cholesterol (LDL-C)/HDL-C, showed a significant difference between the risk and nonrisk groups. Whereas the ratio of apolipoprotein A1 (ApoAI) to apolipoprotein B is the strongest discrimination in children less than or equal to 20 years, the ratio of HDL-C/ApoAI takes this position in the older ones. Apolipoproteins seem to be of considerable importance as risk indicators between offspring who might be at higher risk for later cardiovascular diseases, even in childhood and younger adolescence.