OBJECTIVE To search an optimal method for improving viability of cryopreserved articular cartilage. METHODS Articular cartilage which was sampled from the rabbits were randomly divided into 5 groups. Fresh cartilage was group I, other groups were frozen. Before frozen, other cartilage was exposured in 10% DMSO at 4 degrees C for 30 minutes(group II), 1 hour(group III), 2 hours (group IV), 4 hours(group V), then were stored in liquid nitrogen for 1 week. Viabilities of the chondrocytes were detected by Typan-blue staining, electron transmission microscope, and determination of incorporation 3H-TdR after the temperature returned to normal. RESULTS 1. The cells were injuried at different extent after the cartilage was frozen. In group I, survival rate of cells was 96% and incorporation of 3H-TdR was (4,953.13 +/- 583.27)%, statistic difference was significant between group I and other groups(P lt; 0.01). The microstructure of group I was normal while other groups all had damage of the organella, 2. Structures and functions of cells in group IV were best among frozen groups. Organella were less damaged than group II, III, V, survival rate of cells was 56% and incorporation of 3H-TdR was (1,139.88 +/- 146.39)%, statistic difference was significant between group IV and group II, III, V(P lt; 0.01). CONCLUSION If cartilage are exposured in 10% DMSO at 4 degrees C for 2 hours before frozen, optimal cryopreservation can be achieved.