The paper is devoted to the investigation of the lipid peroxidation level according to measurements of the accumulation level of malon dialdehyde in fragments of the liver tissue of newborn and adult pigs, depending on the cooling rate and cryoprotectants used. The conclusion has been made on the basis of the data obtained. That the lipid peroxidation level in the liver tissue fragments is decreased with the increase of cooling rates. That is activated the least of all with the use of average cooling rate (100 degrees C/min) with dimethylsulphoxide (DMSO) as cryoprotectant in concentrations of 10, 20% and rapid cooling rate (80,000 degrees C/min) with polyethylenglycol-1500 (PEG-1500) and DMSO in analogous concentrations. These cryopreservation data have shown the lowest of the lipid peroxidation level in the liver tissue fragments when comparing one with native tissue (before freezing).