Background: Despite the evidence for the fundamental need for palliative medicine services in the practice of oncology, integration of these medical specialties remains a clinical challenge.; Methods: We reviewed the current literature regarding the practice of palliative medicine in the field of oncology, examining randomized clinical trials of palliative medicine services in advanced cancer, models of palliative medicine delivery, studies of cost effectiveness, and national palliative medicine practice and referral guidelines. In this review, we describe the role of palliative medicine in oncology, including the timing of palliative medicine consultation, models of care delivery, and improvements in patient outcomes.; Results: Randomized controlled trials and national guidelines support early referral of patients with cancer to palliative medicine. Palliative medicine has a fundamental role in symptom management, distress relief, family and caregiver support, and advance care planning. Integration of palliative medicine in oncology improves patient outcomes and decreases healthcare costs. Early involvement of palliative medicine after the cancer diagnosis is supported by national guidelines, but barriers include variable referral patterns among oncologists and the need for an expanded palliative medicine workforce.; Conclusion: Palliative medicine has a wide-ranging role in the spectrum of comprehensive cancer care-from patient diagnosis to survivorship. The entire multidisciplinary care team has a role in providing palliative care in inpatient and outpatient settings. An effective palliative medicine and oncology collaboration improves patient care and quality of life, has broad research and guideline support, and is cost effective.