Background: Intraarticular local anesthetic injection has been therapeutically applied for pain control in various arthritis patients. However, little physiologic effects of local anesthetics on their tissue were known. This study was conducted to determine its effects on the cell proliferation and matrix metalloproteinases (MMP) production of cultured fibroblast like synoviocytes (FLS) derived from synovial tissues of rheumatoid arthritis patients. Methods: Bupivacaine with varying concentrations 0 (control), 0.1, 0.25, 0.5% was applied to experimental cell groups growing as monolayers in culture plates for varying durations 0 (control), 30, 90, 180 seconds in the presence and absence of interleukin-$1eta$. Results: No statistical significances were noted in thymidine incorporation between 0, 30, 90 and 180 seconds exposure groups with 0.5% bupivacaine after 1 day and 2 days. Thymidine incorporation between 0, 0.1, 0.25, 0.5% exposure groups 1 day and 2 days after 90 seconds exposure did not show any differences. After exposure to bupivacaine, there were statistically significant increases in MMP-1 (p=0.025) and MMP-3 productions (p=0.000) of FLS in the absence of IL-$1eta$, but no differences among the groups in the presence of IL-$1eta$. Conclusion: We concluded that in this short-term in vitro study, bupivacaine does not have injurious effect on cultured rheumatoid arthritic joint tissues. The long-term effect cannot be known from this investigation.