Evidence for a role for members of the transforming growth factor β (TGF-β) family of cytokines in the pathogensis of systemic sclerosis and other fibrotic conditions is provided from studies of TGF-β protein and gene expression in lesional biopsy specimens, from altered responses of explanted fibroblasts to TGF-β stimulation which are associated with increased receptor expression on these cells and from genetic data linking TGF-β gene loci to the disease. Of the many effects of TGF-β on fibroblast properties induction of the connective tissue growth factor/Cyr61/NOV (CCN) family members, connective tissue growth factor (CTGF) may be particularly relevant to fibrosis. Moreover, systemic sclerosis (SSc) fibroblasts demonstrate constitutive over expression of CTGF that promotes migration, proliferation and matrix production. Studies of mechanisms regulating constitutive expression of CTGF by SSc fibroblasts are currently being undertaken and indicate that a TGF-β responsive element in the CTGF promoter is involved, although this appears to function independent of the Smad proteins, suggesting that other TGF-β–regulated pathways may be involved. TGF-neutralizing strategies have now been shown to abrogate many animal models of fibrosis, and will soon reach the clinical arena for SSc. These agents will further clarify the role of this ligand in initiating or sustaining fibrosis and offer the exciting possibility of targeted therapy for this disease.