VLDL cholesterol concentrations were determined in 1641 male and 608 female and VLDL apolipoprotein B concentrations in 505 male and 211 female company employees in Westphalia aged 17-70 years. VLDL cholesterol and VLDL apolipoprotein B values were found to be distributed with positive skew in both sexes but were higher in men than in women (median in men: VLDL cholesterol 0.30 mmol/l, VLDL apolipoprotein B 0.066 g/l, median in women: VLDL cholesterol 0.18 mmol/l, VLDL apolipoprotein B 0.047 g/l). In males VLDL cholesterol and VLDL apolipoprotein B were closely correlated to each other (r = 0.757) as well as to triacylglycerols (VLDL cholesterol: r = 0.673, VLDL apolipoprotein B: r = -0.419). In females these observed correlations were weaker. The VLDL cholesterol/VLDL apolipoprotein B ratio was also higher in men (median 4.28 mmol/g) than in women (median 3.15 mmol/g). The ratio correlated to triacylglycerols (men: r = 0.591, women: r = 0.321). The results suggest that the composition of VLDL may be related to triacylglycerols in serum.