Background: Prostate cancer is the most commonly diagnosed cancer in both African American and Hispanic men. Active surveillance is a treatment option for low- or very low-risk prostate cancer survivors, and lifestyle interventions have been found to reduce the disease progression and improve the quality of life for both survivors and their partners. To date, no lifestyle interventions that specifically target African American or Hispanic men and their partners exist. This protocol describes a study that tests the feasibility of a randomized controlled trial, a lifestyle intervention developed to enhance healthy lifestyle and quality of life among African American and Hispanic men on active surveillance and their partners. Methods: A mixed-method study, including a two-arm randomized controlled trial (n = 30 dyads in the intervention arm and n = 10 dyads in the control arm) and in-depth interviews, will be conducted. Intervention arm participants will receive bi-weekly health coaching calls (a total of 12 calls based on Motivational Interviewing), as well as physical activity-specific (e.g., power point slides, print materials about physical activity, and activity trackers for self-monitoring) and nutrition-specific education (e.g., two nutrition counseling sessions from a registered dietitian, print materials about nutrition, and food intake recording for self-monitoring) over 6?months. All participants will be assessed at baseline, month 3, and month 6. Blood will be collected at baseline and month 6 from the prostate cancer survivors. Finally, in-depth interviews will be conducted with subsamples (up to n = 15 dyads in the intervention arm and up to n = 5 dyads in the control arm) at baseline and months 3 and 6 to conduct a process evaluation and further refine the intervention. Discussion: If effective, the intervention may have a higher health impact compared with a typical lifestyle intervention targeting only survivors (or partners), as it improves both survivors� (tertiary prevention) and partners� health (primary prevention). Results from this study will provide important information regarding recruiting racial/ethnic minority cancer survivors and their partners. Lessons learned from this study will be used to apply for a large-scale grant to test the impact of the dyadic intervention in a fully powered sample.