Interstitial lung disease (ILD) is the leading cause of mortality in patients with systemic sclerosis (SSc), which is also known as scleroderma. Two randomized clinical trials in patients with SSc-related ILD have shown that oral or intravenous cyclophosphamide is associated with modest but significant or near-significant improvements in lung function, dyspnea, and physical function. In addition, the Scleroderma Lung Study and an observational study showed that baseline forced vital capacity less than 70% and moderate fibrosis on thoracic high-resolution CT are predictors of response to cyclophosphamide therapy and/or survival, whereas active alveolitis on bronchoalveolar lavage is not. Newer therapies for SSc patients with ILD include mycophenolate mofetil, tyrosine kinase inhibitors (imatinib, dasatinib), and anti-interleukin-13 monoclonal antibody. Several uncontrolled trials have reported favorable results of mycophenolate mofetil in SSc-related ILD. A randomized double-blind controlled trial by the Scleroderma Lung Study Research Group is currently comparing the efficacy and safety of mycophenolate mofetil versus oral cyclophosphamide.