Rheumatoid arthritis and periodontitis are chronic inflammatory diseases associated with tissue destruction that is mediated in part by elevated levels of cytokines (e.g. interleukin-1 and tumor necrosis factor). Differential screening of a human synovial fibroblast cDNA library for interleukin-1 induced genes revealed a clone identical to the gene encoding human bone morphogenetic protein-2. Northern blot analysis of human synovial fibroblast mRNA confirmed up-regulation of bone morphogenetic protein-2 in the presence of interleukin-1. Utilizing a specific antibody, levels of bone morphogenetic protein-2 protein in conditioned medium from synovial fibroblasts were also up-regulated in the presence of interleukin-1. This is the first report of the production of bone morphogenetic protein-2 by synovial fibroblasts, and the first report of its up-regulation in response to interleukin-1. However, interleukin-1 did not induce bone morphogenetic protein-2 mRNA in human gingival fibroblasts.