Chronic GVHD (cGVHD) is a potentially devastating late complication of allogeneic stem cell transplantation. To better understand current diagnostic and treatment practices regarding this complication, we mailed a self-administered survey to 188 adult and pediatric transplantation programs. The survey collected data on experience with therapies for cGVHD and presented 6 vignettes to assess agreement about the diagnosis, clinical management, grading, and prognosis of patients with symptoms of cGVHD. Response rate to the survey was 51%. Of the respondents, 28% felt they had "great success" in treating patients with systemic corticosteroids, and 13% had similar success with cyclosporine or mycophenolate mofetil; less success and experience were reported with other agents. Respondents estimated an average 3-year, nonrelapse mortality of 16% (95% CI, 14%-19%) for patients assessed to have limited disease and 39% (95% CI, 36%-43%) for extensive disease. Analysis of responses to the 6 vignettes showed that agreement was greatest for supportive care issues, willingness to enroll patients in clinical trials, and use of systemic immunosuppression for symptomatic cGVHD. Less agreement was seen for diagnosis and management when cGVHD manifestations were atypical or less severe, the decision of whether to taper immunosuppression in the face of stable symptoms, and for assignment of mild, moderate, or severe cGVHD grades. Most respondents were willing to use systemic immunosuppression to treat symptoms that they believed to be caused by cGVHD, but differences of opinion about cGVHD diagnosis and disease activity resulted in significant practice variation. Low estimates of treatment success were noted and reflected an overall pessimism about the success of therapy for cGVHD. We conclude that studies defining appropriate diagnostic pathways, criteria for disease activity, and prognosis could help standardize management of cGVHD. There is an urgent need to develop and test new approaches to treat cGVHD.