ABSTRACT Though cancer remains a leading cause of death among Hispanic/Latinx populations in the United States and Hispanic/Latinx patients routinely experience disparities in cancer-related care, the overwhelming majority of behavioral and psychosocial oncology research continues to focus on non-Hispanic whites (NHW). Compared to NHW, individuals who identify as Hispanic and Latinx are more likely to: 1) be diagnosed with advanced stage disease, 2) experience poor quality of life, and 3) experience inadequate cancer-related care such as pain management. Hispanic/Latinx patients also endure greater levels of pain compared to other racial and ethnic groups, and are more likely to express concerns about cancer pain management due to inadequate analgesia, less pain relief, and poor patient-provider communication. Across all of pain management, Hispanic/Latinx populations have lower access to chronic pain treatments compared to others (particularly if they are primarily Spanish speaking), and inadequate access to suitable pain treatments, which may contribute to medication misuse, emotional distress, and diminished quality of life. In addition to socially determined disparities, language barriers are a key challenge limiting compliance with pharmacologic treatments and access to essential pain management services. The overwhelming lack of services available in Spanish, compounded by cultural discordance within available services, serves as an additional barrier to engagement with Hispanic/Latinx communities. Additionally, there is a need for internet-based cancer care services provided in Spanish and formatted for use via mobile devices, which must integrate unique features of culture into care programs. Our team has developed and validated a web-based pain coping skills training (PCST) intervention (painTRAINER), available via Internet-enabled devices and smart phones, that retains critical features of empirically validated and effective in-person PCST interventions. PainTRAINER is a maximally accessible, interactive and personalized intervention that does not require clinic visits or therapist involvement. PainTRAINER’s effectiveness for pain management is well-established via NIH-funded trials, but is only available in the English language which leaves a gap in the ability to extend care to Spanish-speaking patients with limited English proficiency. In collaboration with Hispanic and Latinx community organizations, community advisory boards, patient advocates, and bilingual health experts, we will follow a stepwise community-engaged and culturally-informed adaptation and translation of the painTRAINER program including: develop a community advisory board (CAB) and a community-based programmatic review panel (PRP); perform an initial intervention translation process; critically evaluate core functions and theoretical constructs of painTRAINER; engage the CAB and PRP to evaluate and further critique all translations; develop painTRAINER-Spanish to...