Background: Multiple studies illustrate the benefits of combined palliative and standard cancer care, but oncology practices need guidance to fill existing gaps in delivering high quality palliative care (PC) to cancer patients. As a first step, ASCO and the American Academy of Hospice and Palliative Medicine (AAHPM) sought to develop a consensus definition of which PC aspects are within the purview of general adult oncology practice in the United States. Methods: An ASCO and AAHPM steering group used existing publications to define 9 domains of PC in oncology: Symptom Assessment and Management (A&M), Psychosocial A&M, Spiritual and Cultural A&M, Communication and Shared Decision-Making, Care Planning, Appropriate Palliative Care and Hospice Referral, Coordination and Continuity of Care, Carer Support, and End-of-Life Care. Within each domain, key PC activities were itemized and described (e.g. pain assessment using a standardized scale at every clinical encounter), totaling 966 activities. A 31-member multidisciplinary panel participated in a modified RAND Delphi process, rating each activity on a 9-point scale according to 3 constructs: importance, feasibility, and scope of practice. Composite scoring categorized activities as either reasonably within scope of oncology practice, uncertain, or typically not in scope. Results: The response rate for each round was 94%. Notable panelist concerns included the breadth of palliative care practice, the varied access that oncology practices have to PC resources, and the varied individual knowledge and comfort with specific activities. Despite multiple small ranking changes between surveys, only 41 activities changed in scope of practice category. Of 966 activities, 62% were ranked as reasonably within scope of oncology practice, 36% were uncertain, and 2% were typically not in scope. Conclusions: Despite the diverse range of PC activities, panelists strongly agreed that more than half were reasonably within the scope of adult medical oncology practice. These items provide a foundation for improving palliative care delivery within an oncology practice, with suggestions for future performance measures and quality improvement activities.