This article offers an approach to the assessment of frail older adults with complex needs that has been used by the University of North Carolina at Chapel Hill Program on Aging as both a care delivery and a teaching strategy. The patient is assessed simultaneously by different disciplines to develop a holistic and practical plan of care. It is termed "arena assessment," borrowing from the pediatric literature on transdisciplinary assessment of children. The article explores the benefits and limitations of this approach for patients and families, as well as for professional learners. Case examples illustrate use of the model from community-based to institutional care.