The interaction of liposomes containing different amounts of cholesterol with human serum low density lipoproteins was investigated. Efficiency of the interaction depended on the cholesterol content of liposomes and was highest for liposomes with the maximal cholesterol/phospholipid molar ratio. The latter selectively and effectively interacted with low density lipoproteins, with up to 90% of lipoprotein particles interacting with liposomes in serum. Fusion of the particles with liposomes was observed during the interaction.