Social determinants of health and unmet social needs are directly related to cancer outcomes, from diagnosis to survivorship. If identified, unmet social needs can be addressed in oncology care by changing care plans in collaboration with patients' preferences and accounting for clinical practice guidelines (eg, reducing the frequency of appointments, switching treatment modalities) and connecting patients to resources within healthcare organizations (eg, social work support, patient navigation) and with community organizations (eg, food banks, housing assistance programs). Screening for social needs is the first step to identifying those who need additional support and is increasingly recognized as a necessary component of high-quality cancer care delivery. Despite evidence about the relationship between social needs and cancer outcomes and the abundance of screening tools, the implementation of social needs screening remains a challenge, and little is known regarding the adoption, reach, and sustainability of social needs screening in routine clinical practice. We present data on the adoption and implementation of social needs screening at two large academic cancer centers and discuss three challenges associated with implementing evidence-based social needs screening in clinical practice: (1) identifying an optimal approach for administering social needs screening in oncology care, (2) adequately addressing identified unmet needs with resources and support, and (3) coordinating social needs screening between oncology and primary care.