Biodistribution in organs and accumulation in macrophages of GMDP entrapped in phosphatidylcholine liposomes were studied by method of double isotopic tracer (14С/125I). Peptide release from liposomes in blood was established up to 90 % for 6 hours. At the same time, liposomal peptide eliminated gradually from blood, retained in the liver, spleen and lungs and accumulated in macrophages of these organs.