The interaction of liposomes containing different amounts of cholesterol with low-density lipoproteins from human serum was investigated. The efficiency of the interaction was found to depend on the cholesterol content of the liposomes and was highest for liposomes with the maximum cholesterol:phospholipid molar ratio. These liposomes selectively and effectively interacted with low-density lipoproteins; up to 90% of lipoprotein particles interacted with liposomes in serum. Fusion of particles with liposomes was observed during the interaction.