The 2005 National Institutes of Health (NIH) consensus criteria for chronic GVHD have set standards for reporting. Many questions, however, have arisen regarding their implementation and utilization. To identify perceived areas of controversy, we conducted an international survey on diagnosis and scoring of chronic GVHD. Agreement was observed for 50-83% of the 72 questions in 7 topic areas. There was agreement on the need for modifying criteria in six situations: two or more distinctive manifestations should be enough to diagnose chronic GVHD; symptoms that are not due to chronic GVHD should be scored differently; active disease and fixed deficits should be distinguished; a minimum threshold body surface area of hidebound skin involvement should be required for a skin score of 3; asymptomatic oral lichenoid changes should be considered a score 1; and lung biopsy should be unnecessary to diagnose chronic GVHD in a patient with bronchiolitis obliterans as the only manifestation. The survey also identified 26 points of controversy. Whenever possible, studies should be conducted to confirm the appropriateness of any revisions. In cases where data are not available, clarification of the NIH recommendations by consensus is necessary. This survey should inform future research in the field and revisions of the current consensus criteria.