Abstract: The invention relates to a novel, advantageous process for the preparation of liposomes for the inclusion of water-soluble or hydrophilic substances or mixtures of substances, which process provides the surprising advantage, in comparison with known processes, that the proportion of substances or mixtures of substances actually included is increased and which, when used pharmaceutically, provides the advantage of sterile working conditions. In this process, a mixture consisting of at least one phospholipid and customary lipophilic excipients is subjected to a mobile carrier phase consisting of carbon dioxide and a polar organic solvent (modifier) under supercritical pressure and temperature conditions, the compressed mixed phase is reduced to normal pressure and transferred to an aqueous phase comprising a substance having water-soluble or hydrophilic properties for encapsulation in liposomes.