To investigate the role of transforming growth factor beta (TGF-beta)in the regulation of the gene expression of matrix metalloproteinase 13 (MMP-13) in the human hyaline chondrocytes.The human hyaline chondrocytes harvested enzymatically and cultured in DMEM supplemented with 20% fetus calf serum were divided into 7 groups. Group 1 was used as a control, and 1 ng/ml TGF-beta (group 2), 10 ng/ml TGF-beta (group 3), 100 ng/ml TGF-beta (group 4), 1 ng/ml TGF-beta+ 10 ng/ml IL-1beta (group 5), 10 ng/ml TGF-beta+ 10 ng/ml IL-1beta (group 6), and 100 ng/ml TGF-beta+ 10 ng/ml IL-1beta (group 7) were given for 12-hour coculture. The MMP-13 mRNA levels of passaged human hyaline chondrocytes were assessed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time fluorescent quantitative PCR.TGF-beta can increase the MMP-13 mRNA level respectively in the passaged hyaline chondrocytes. In the multi-factor treated groups, TGF-beta can decrease the MMP-13 mRNA level respectively and there was significant difference between groups (P0.05). The level of MMP-13 mRNA expression had significant coherence with the dosage of TGF-beta.The above results show that human chondrocytes express MMP-13 mRNA. TGF-beta could cause a dose-dependent stimulation on MMP-13 gene expression in human chondrocytes and have a potent effect of antagonizing IL-1beta in osteoarthritis. TGF-beta may play a crucial role in the occurrence and development of osteoarthritis through regulating MMP-13.