Oral mucositis is a frequent side effect of cancer treatment and can lead to delayed treatment, reduced treatment dosage, altered nutrition, dehydration, infections, xerostomia, pain, and higher healthcare costs. Mucositis is defined as "inflammatory lesions of the oral and/or gastrointestinal tract caused by high-dose cancer therapies. Alimentary tract mucositis refers to the expression of mucosal injury across the continuum of oral and gastrointestinal mucosa, from the mouth to the anus" (Peterson, Bensadoun, & Roila, 2008, p. ii122). Evidence demonstrates that oral mucositis is quite distressing for patients. In addition, the majority of oncology nurses are unaware of available guidelines related to the care of oral mucositis. A multidisciplinary Oral Mucositis Committee was formed by the University of Iowa Hospitals and Clinics to develop evidence-based prevention and treatment strategies for adult and pediatric oncology patients experiencing oral mucositis. The first step was implementing an evidence-based nursing oral assessment. The Iowa Model was used to guide this evidence-based practice initiative. The Oral Assessment Guide (OAG) is reliable and valid, feasible, and sensitive to changing conditions. The OAG was piloted on an Adult Leukemia and Bone Marrow Transplant Unit leading to modification and adaptation. The pilot evaluation found 87% of patients had an abnormal oral assessment involving all categories in the tool. Nursing questionnaires showed that staff (8/23; 35% response) felt they were able to identify at risk patients using the OAG (3.3; 1-4 scale), and the tool accurately identifies mucosal changes (2.9; 1-4 scale). A knowledge assessment found nurses correctly identified OAG components 63% of the time. Unlike results from a national survey, most University of Iowa Hospitals and Clinics nurses (63%) were aware of national guidelines for prevention and treatment of oral mucositis. Developing an evidence-based nursing policy and updating documentation systems was done before implementation occurred. Computer-based and printed educational materials were developed for nursing staff caring for oncology patients. Team members were responsible for facilitating adoption in clinical areas. After organizational roll out, the nursing assessment was documented in all patients 87% of the time, and 99% for inpatients. The highest risk population, head and neck cancer patients receiving radiation, had documentation in 88% of audited visits. Other clinics required further work. Changing the system to the electronic medical record created an additional need for integration of the evidence-based practice with housewide documentation of oral assessment being completed 60.9% of the time. Use of an evidence-based assessment is the first step in a comprehensive program to reduce a common and highly distressing side effect of cancer treatment. Nursing documentation of oral assessment is well integrated on inpatient units. Opportunities for improvement remain in ambulatory care. Multidisciplinary team collaborations to expand evidence-based assessment and research questions generated from this work will be shared.