The aim of this study was to investigate the effects and underlying mechanisms of calcitonin (CT) on interleukin 1 beta (IL-1 beta) stimulated human chondrocytes. IL-1 beta (5 ng/mL) was added into chondrocytes to establish osteoarthritis (OA) model in vitro. Different concentrations of CT (0.1, 0.5, 1, 5, 10 and 50 nM) were used for treating IL-1 beta stimulated chondrocytes. Cell viability of chondrocytes was measured by cell counting kit-8 (CCK8) method. Western blotting was performed to evaluate the expression of matrix metalloproteinases (MMP-13), tissue inhibitor of metalloproteinases 1 (TIMP-1), p50 and p38. CT inhibited MMP-13 expression and promoted TIMP-1 expression in the IL-1 beta stimulated human chondrocytes. The CT-mediated alteration of MMP-13/TIMP-1 ratio was partially attributed to the inactivation of the p50- nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B) pathway by suppressing p50 in IL-1 beta stimulated chondrocytes. CT might play a protective role in IL-1 beta stimulated OA model via p50-NF-kappa B pathway.