Abstract.A very strong association between phenotype Lp(a +) and presence of pre‐β1‐lipoprotein has been observed in two series of healthy young adults. The data are in agreement with the view that pre‐β1‐lipoprotein is identical to the lipoprotein carrying the Lp(a) antigen: the Lp(a) lipoprotein. Lp(a) antigen/pre‐β1‐lipoprotein occurred more frequently in persons with a positive than with a negative family history of coronary heart disease, though this trend was not statistically significant. Occurrence of Lp(a) antigen/pre‐β1‐rlipoprotein was not correlated with smoking or with the use of contraceptive pills.