Oral mucositis (OM)-related outcomes constituting a meaningful clinical advance in bone marrow transplant patients were considered by an interdisciplinary panel. Meaningful outcomes are essential in product development for OM, a condition without effective prevention or treatment. The most important outcomes to measure, the feasibility of measuring these in a clinical trial, and clinically meaningful differences in these outcomes were determined by the panel. Most important are reduction in oral pain and use of opioid analgesics, improvement in oral intake and quality of life, and reduction of hospitalization duration. Reduction in the severity of OM measured by an objective evaluation of oral mucosa could provide insight regarding the biologic activity of an intervention. Further data are required to define the precise relationship between reduction in visible OM and improvement in outcome. Minimally, clinical trials for OM should assess oral pain, opioid use, oral intake, and include objective assessment of OM.