Cytokines and chemokines play important roles in both autoimmune and infectious arthritides. Here we describe the cytokines and chemokines induced by Ross River (RR) virus infection of synovial fibroblasts and macrophages in vitro. RR virus is the aetiological agent of epidemic polyarthritis (EPA), a principally acute and chronic rheumatic disease affecting up to 7,000 Australians annually. Infected fibroblasts increased expression of mRNA coding for monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), and granulocyte-macrophage colony-stimulating factor. MCP-1, IL-8, macrophage inflammatory protein-2, and to a lesser extent interferon γ-induced protein-10 mRNA were upregulated in infected macrophages. Expression of MCP-1 is consistent with the predominantly monocytic effusion found in EPA synovia.