A U937 cell model, in which Bcl-2 expression was suppressed, was established by transfering antisense bcl-2 gene into U937 cell. The model cell had normal growth and survival. Crystal violet assay with actinomycin D and ELISA indicated that the activity and concentration of TNFα in the model cell supernatant had no change, but mouse thymocyte proliferation assay revealed that IL-1 activity increased in the supernatant siginificantly. The results suggested that Bcl-2 expression has no effect on TNFα production and its activity, but it may suppress the expression or activity of IL-1. The study on the regulation of IL-1 and TNFα expression by bcl-2 may provide some beneficial data for elucidating the mechanism of bcl-2 action.