Two types of binding sites for high-density lipoproteins (Kd=1 μg/ml and 20 μg/ml) were identified on human fetal hepatocytes and designated as P1 and P2. Ligand blotting has shown that P1 site is protein with Mr 100 kD and P2 site involves two proteins with Mr 105 and 110 kD. P2 proteins were not detected when incubation with ligands was shortened from 24 h to 30 min. Molecular weight and activity of P1 did not change considerably after reduction of disulfide bonds.