The aim of the present study was to investigate the effects of cinobufocini on nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2) and the production of cytokines induced by tumor necrosis factor-α (TNF-α) in the A549 cell line. A549 cells were incubated with cinobufocini at different concentrations for 24, 48 or 72 h. Cell proliferation was examined by the WST-8 assay. The expression of NF-κB, COX-2 and inhibitor κBα (IκBα) was studied by western blotting. The NF-κB-dependent luciferase rporter (3xκB-luc) was transfected for 24 h, the cells were treated with the reagents for 24 h, and the transcriptional activity of the NF-κB promoter was detected by a luciferase assay. The levels of IL-6 and IL-8 mRNA were detected by reverse transcription-polymerase chain reaction. We found that cinobufocini inhibited NF-κB p65 expression and the transcriptional activity of the NF-κB promoter induced by TNF-α compared with the control in the nuclei of A549 cells. Moreover, induced COX-2 expression was blocked by cinobufocini and was correlated with a reduction in the activated p65 subunit of NF-κB. Additionally, the levels of IL-6 and IL-8 mRNA induced by TNF-α were significantly suppressed by the addition of cinobufocini. In conclusion, these results suggest that the anti-inflammatory effects of cinobufocini are dependent on the NF-κB/COX-2 pathway in A549 cells, thereby providing a possible anticancer mechanism for the compound.