PURPOSE: Religion and spirituality play a role in coping with illness for many cancer patients. This study examined religiousness and spiritual support in advanced cancer patients of diverse racial/ethnic backgrounds and associations with quality of life (QOL), treatmentpreferences, and advance care planning. METHODS: The Coping With Cancer study is a federally funded, multi-institutional investigation examining factors associated with advanced cancer patient and caregiver well-being. Patients with an advanced cancer diagnosis and failure of first-line chemotherapy were interviewed at baseline regarding religiousness, spiritual support, QOL, treatment preferences, and advance care planning. RESULTS: Most (88%) of the study population (N = 230) considered religion to be at least somewhat important. Nearly half (47%) reported that their spiritual needs were minimally or not at all supported by a religious community, and 72% reported that their spiritual needs were supported minimally or not at all by the medical system. Spiritual support by religious communities or the medical system was significantly associated with patient QOL (P = .0003). Religiousness was significantly associated with wanting all measures to extend life (odds ratio, 1.96; 95% CI, 1.08 to 3.57). CONCLUSION: Many advanced cancer patients’ spiritual needs are not supported by religious communities or the medical system, and spiritual support is associated with better QOL. Religious individuals more frequently want aggressive measures to extend life.