Serum apolipoprotein (apo) A-I and apo B were measured along with lipoprotein cholesterols in two cross-sectional surveys 4 years apart on 1728 children and young adults in the Bogalusa Heart Study. Tracking was assessed in terms of correlation coefficients and persistence at extreme quintiles. The year 1 vs year 4 correlation coefficients ranged from 0.24-0.45 for apo A-I and 0.57-0.59 for apo B among different race and sex groups. Corresponding values for serum high-density (HDL) and low-density (LDL) lipoprotein cholesterols were 0.39-046 and 0.64-0.67, respectively. Thirty-one percent of those individuals who had apo A-I levels in the highest quintile at year 1 remained in this quintile at year 4; for apo B, 50% of those in the highest quintile persisted in this rank at year 4. On the other hand, for those individuals in the lowest quintile at baseline, 36% for apo A-I and 53% for apo B remained in this rank at follow-up. The best predictor of follow-up apolipoprotein levels was the baseline level. Since tracking of apo A-I and apo B was similar in magnitude to those of HDL-cholesterol and LDL-cholesterol, the measurement of either lipoprotein cholesterols or apolipoproteins may be equally useful in terms of intervention strategies to control coronary heart disease risk.