Cancer patients have unique metabolic and nutritional requirements that require multi-disciplinary approaches for optimal management. The impact of nutrition on the health of cancer patients holds inherent challenges in assessment and measurement and factors implicated in energy metabolism, appetite regulation, body composition, inter-organ cross talk, hormone alterations, malabsorption, and complications of therapies must be considered. Cancer patients may experience deficits in essential nutrients; however. the extent to which restoration of deficits improves outcomes remains poorly characterized. This Special Issue on clinical nutrition will emphasize studies conducted in humans that have evaluated the status of micro- or macronutrients, nutrient requirements, body composition, and metabolic dysregulation in the oncology setting. The work presented will be of special interest to nurses, dietitians, physicians, and other practitioners working in the oncology setting. Effective strategies for combating disease-associated malnutrition will be realized by combined approaches and collaboration among multiple disciplines.