Pain affects approximately two thirds of patients with advanced, incurable cancer, with rates approaching 90% near the end-of-life. Advanced cancer pain can be notoriously severe, degrading patients' emotional, social, and functional wellbeing. Advanced cancer pain is a multidimensional process that requires a holistic approach to care. Unfortunately, in real world settings pharmacotherapy is often the only treatment available to patients. Mindfulness has been defined as a directed, flexible cognitive process that allows a person to observe thoughts and emotions in the moment, as opposed to reacting to them. Applied to chronic pain, mindfulness seeks to decouple the sensory experience of pain from cognitive interpretations and emotional reactions – a ideal strategy for advanced cancer pain given the close connection between pain sensations and cognitiveaffective responses (e.g. fears of cancer progression and death). Mindfulness has been proven effective for chronic pain from a variety of non-cancer diagnoses, but studies of mindfulness for advanced cancer pain are lacking. Traditional mindfulness programs, which involve 8 weeks of lengthy group-based trainings with daily practice, are impractical and inaccessible to most advanced cancer patients. Moreover, existing programs are not adapted to this populations' physical limitations, often intense emotional and existential distress, nor do they support other vital aspects of self-management required to successfully cope with cancer pain at home. The object of this proposal is to develop, refine and pilot CHAMP (Cancer Health Application for Mindfulnessbased Pain treatment), a novel smartphone application to deliver mobile mindfulness training tailored to the needs of patients with advanced cancer pain. To complement mindfulness practice, CHAMP will integrate multimedia cancer pain psychoeducation and medication support, maximizing patients' ability to cope and selfmanage. This project is made feasible by the team's ability to leverage mindfulness content, multi-media cancer pain psychoeducation, and design features from two existing mHealth projects (R21 NR017745, and R00 MD010468). In Aim 1a, the study team will develop and program CHAMP, involving the target patient population for multiple levels of review and revision. In Aim 1b, a small pre-pilot will be conducted (N=5) in order to refine the app prior a pilot study. In Aim 2, 20 patients with persistent pain from a variety of advanced solid malignancies at a major academic cancer center will be assigned to use CHAMP for 8 weeks. Findings will illuminate the feasibility of data collection, allow exploration of meaningful trends, and enable the design of a future randomized trial to test the ability of CHAMP to improve pain and QOL for advanced cancer patients. The sum result of this project will be a tailored, mindfulness intervention which - if proven effective - has great potential to scale and make mind-body treatment available to a population that suffers disproportionately from chronic pain and currently has extremely limited access to effective, non-pharmacologic management.