Abstract Introduction Introduction: Sexual health is a central dimension of overall health and quality of life, yet it remains a largely neglected component in vulnerable populations such as cancer patients. Colorectal cancer (CRC) is currently one of the most prevalent types of cancer worldwide, and its treatments negatively affect people's sexual and relational health and well-being throughout the course of the disease. Notwithstanding the negative impact of treatments on different dimensions of sexual functioning (e.g., changes in sexual desire, sexual arousal, and orgasm experience), on the experience of pleasure and sexual satisfaction of people with CRC, access to specialized support is often hampered due to organizational, geographical, and attitudinal barriers (e.g., stigma). Given their intimate nature, accessibility, and convenience/flexibility, smartphone-based digital interventions can help bridge this gap and be an important supportive tool to effectively address unmet sexual health care needs in people with CRC. However, there is still a lack of studies evaluating the acceptability, feasibility, and effectiveness of smartphone-based sexual health promotion programs for people with CRC. Objective Objectives: The objective of this study is to evaluate the acceptability, feasibility, and preliminary efficacy of Anathema, a program developed for the promotion of the sexual health of CRC survivors. Methods Methods: A randomized controlled pilot study is underway and involves 30 CRC survivors randomly assigned to an experimental group (with access to the program) and a waiting list control group (treatment as usual). The program was structured into five modules to be completed in 8 weeks and developed based on the principles of Cognitive-Behavioral Therapy. An institutional Ethical Board approved the study. Acceptability, usability, and feasibility of Anathema were the primary outcomes defined in this study. Sexual and relational satisfaction, sexual functioning and distress, sexual pleasure, and quality of life were defined as secondary outcomes. Results Results: The participatory design used throughout the different phases of this project anticipates a good acceptability of the program among its primary users. It is also expected that the program and the design adopted will be suitable for the future implementation of an RCT. Improvement in levels of sexual and relationship satisfaction, sexual pleasure, quality of life, and a decrease in levels of sexual distress in people who use the program compared to people in the waiting list group, are also expected. Conclusions Conclusions: Anathema is a promising program for promoting sexual health and quality of life in CRC survivors. Funding source: This project is jointly funded by the European Commission through the AAL Program (ref. AAL-2020-7-133-CP) and its Member States: Fundação para a Ciência e a Tecnologia, in Portugal (AAL/0005/2020), Austrian Research Promotion Agency (FFG), in Austria, and ZonMw, the Netherlands Organization for Health Research and Development, in the Netherlands. Disclosure No.