Prolonged storage of isolated photosystem 2 (PS2)-enriched subchloroplast particles in the frozen statě leads to a decrease of the PS2 activity and to an increase of the energy transfer between chlorophyll (Chl)-proteins of the light-harvesting chlorophyll a/b (LHC)-PS2 complex. The energy transfer was less influenced than the PS2-mediated electron transport at freeze-thaw treatment of PS2 particles. The change of these parameters was not affected by the rate of freezing. The addition of cryoprotectants such as glycerol, trehalose or saccharose in the suspension medium prior to freezing preserved fo a different extent the PS2-mediated electron transport and the energy transfer between the Chl molecules of the LHC-PS2 complex.