Interleukin-1beta is up-regulated in the presence of Helicobacter pylori infection. H. pylori infection was associated with E-cadherin methylation. In this study, we examined if IL-1beta could induce promoter methylation of E-cadherin in human gastric cancer cell lines TMK-1, MKN-74 and MKN-7. Cells were treated with IL-1beta (0.025, 0.1, 0.25, 1.0, 2.5 ng/mL) for 6, 12 and 24h. Methylation status was determined by MSP and sequencing. The effects of IL-1beta or H.pylori on the cells, and after blockade with interleukin-1 receptor antagonist (IL-1ra) were tested. Promoter methylation of E-cadherin was induced in all three cells treated with IL-1beta or co-cultured with H. pylori. Treatment of IL-1ra could reverse the phenomena. Our study indicated that IL-1beta is an important step in mediating E-cadherin methylation.