Oral complications resulting from cancer therapies cause various acute (mucositis, saliva changes, taste alterations, infection, bleeding) and late toxicities (mucosal atrophy and xerostomia) that may be underreported, underrecognized, and undertreated. Disruptions in the function and integrity of the mucosal lining of the oral cavity are a particularly important problem in patients receiving chemotherapy and radiotherapy. This risk results from multiple factors, including high rates of cellular turnover for the lining mucosa, a diverse and complex microflora, and trauma to oral tissues during normal oral function. Recent advances in cancer treatment have led to changes in the incidence, nature, and severity of oral complications. Management of oral toxicities is needed to ensure optimal long-term oral health and general well-being. Acute oral toxicities of cancer therapies may be reduced, but the significant impact of long-term complications requires increased awareness and recognition to promote prevention and appropriate intervention. It is essential that a multidisciplinary approach be used for oral management of the cancer patient before, during, and after cancer treatment. It is therefore important for the primary oncologist to be aware of these complications so that appropriate measures can be implemented in a timely manner. Prevention and management are best provided via multidisciplinary health-care teams, which must be integrated and communicate effectively in order to provide the best patient care in a coordinated manner at the appropriate time. This chapter explains the assessment and management of oral complications from treatment in cancer patients.