Biologic resurfacing of the damaged joints is an area of great interest and clinical promise because of the limited potential ofdamaged articular cartilage healing. Several methods such as spongiolization. joint dehridement and ahrasion of suhchondral hone. perichondral grafts, and osteochondral grafts have heen used to repair cartilage defects, but the results were not satisfactory. Rccently autologous chondrocyle transplantation with a pcrioslcal patch was paid an altention for its advantage , the regeneration with hyalin cartilage. But it have many disadvantages such as too expensive cost. second staged operation, and technically difficult to isolatc chondrocytes from a small volume of donor site, so we performed that a definecl cartilaee delect in the ribbit patella was treated with transplanta1ion of in virto expanded allogenic chondrocvtes and then compared with an autologous chondrocytes transplantation. Adult rabbits were used to transplant autogenously and allogenously and allogenically harvested and in vitro cultured chondrocytes into patellar chondral lesions that had been made previously 3x 3mmin size , extending down to the calcified zone. Chondrocytes were isolated in the femoral condyle of the opposite knee or othe rabbit knee. And then enzymatic digestion ( collagenase A and DNase I ) was performed for 5 hours room temperature in a spinner bottle and cells were seeded in a 25cm2 culture flask in Dulheccos modified essential medium (DMEM), supplemented with l0% fetal hovine serum (FBS). The culture medium was changed twice weekly. After 14 days of culture, the cells were isolated hy irypsinization and transplanted into previously made chondral defects with an autogenous periosteal patch taken from the medial aspect of tibia. Healing ol' the defects was assessed by gross examination, immunohistochemical stain, and light microscope with hematoxylin-eosin stain at 8, 16, and 24 weeks. Allogenic and autologous chondrocytes transplantation significantly increased the amount of newly tormed repair tissue compared to that found in control knees in which the Jesion was solely covered hy a periosteal patch. The repair tissue, however, had a tendency of incomplete bonding to adjacent cartilage. This study shows that allogenic and autologous articular chondrocytes that have heen expanded for 2 weeks in vitro can stimulate the healing phase of chondral lesion. There is no signilicant diffcrence hetween allogenic and autologous chondrocytes transplantation.