T cells play a critical role in rheumatoid arthritis. They are probably continuously involved in pathogenesis, from the initiation to the chronic stage. As recent studies have demonstrated, the part they play in rheumatoid arthritis is closely linked to the roles of macrophages and mesenchymal cells, because they all interact through autocrine, paracrine, and cell-contact pathways. This paper reviews recent work and research regarding the specific role of T cells in the pathogenesis of rheumatoid arthritis.