Respiration and oxidative phosphorylation of the rat kidney cortex mitochondria are studied as affected by low temperatures and cryoprotectants. There is no change in respiration in state 2 during freezing and thawing of the rat kidney cortex slices both in case of using the succinate oxidation substrate and alpha-ketoglutarate. Respiration in state 3 is inhibited in the medium with alpha-ketoglutarate during freezing under protection of polyethylene oxide-100 (PEO-100) and glycerol, and does not significantly change in case of using dimethyl sulphoxide (DMSO). The effectiveness of cryoprotectants used in the experiments reduces in the following sequence: DMSO--glycerol--PEO-100. Preservation of the main mitochondria function, ATP synthesis, is shown to be possible for the kidney cortex slices exposed to freezing and thawing.