A defect was artificially created on the joint surface of the distal ends of both femoral bones in 30 rabbits. After digestion of the cartilage fragment, the resulting cells were cultured in vitro and multiplied. The multiplied autologous chondrocytes were implanted at the point of the defect under a periosteum patch in the right knee (group I). The defect in the left knee was covered with periosteum alone (group II). The regenerates obtained in this way were evaluated at 4, 8, and 12 weeks after surgery, macroscopically for even coverage of the surface of the defect and the quantity of regenerate in proportion to the surrounding healthy tissue, microscopically with H + E stain for the nature of the prevalent tissue, integration with the environment, the presence of necrosis, the formation of isogenous groups of cells, and the formation of cracks.<br /> In the macroscopic evaluations at weeks 4, 8, and 12, the presence of regenerate was discovered in group I in approximately the same quantities as in the surrounding cartilage. The group II joints were found to have less satisfactory repair of the lesion.<br /> In the microscopic evaluation, group I was found histologically to have cartilage tissue well integrated with the environment and chondrocytes forming isogenous groups of cells. In group II most of the joints were found to have incomplete or no integration with the surrounding tissue, with necrosis and cracking.<br /> The reconstruction of defects in articular cartilage using autologous chondrocytes and periosteum produced a regenerate macroscopically similar to the surrounding articular cartilage. The results obtained by regeneration of articular cartilage using autologous chondrocyte grafts and periosteum were superior to those obtained with isolated periosteum grafts.