Systemic sclerosis (SSc) is an autoimmune/connective tissue disease with complex pathogenesis involving immune system dysregulation, leading to fibrosis. Inflammatory and autoimmune aspects of this disease overlap systemic lupus erythematosus (SLE), a disease shown clearly to respond to MMF. Activated T-cells, the probable target of MMF in SLE, likely also play an important role in SSc pathogenesis. Evidence for this includes the similarity of SSc skin disease to chronic graft versus host disease, a disease in which T-cells play a critical role. MMF has proven one of the most effective medications to date for SLE and associated nephritis [1]. It also appears to be active in polymyositis and dermatomyositis, disease that also show significant overlap with SSc [2]. Myositis can also be a feature of SSc, suggesting that his disease manifestation might be particularly likely to respond to MMF. MMF inhibits inosine monophosphate dehydrogenase, the rate-limiting enzyme in synthesis of guanosine nucleotides. It blocks the type II isoform found in activated lymphocytes more potently than the type I isoform inhibiting both T- and B-lymphocytes [3]. In SSc, mycophenolate has been tried after anti-thymocyte globulin in one small open label study with efficacy with a significant improvement in skin score [4]. However, MMF has not been tried alone inSSc and has not been tried in muscle disease associated with SSc. In this study, we will test the safety and efficacy of MMF in SSc. In this study all study patients will receive the medication.