Assess the feasibility, acceptability, and preliminary efficacy of a healthy lifestyle website, SurvivorSHINE (www.survivorshine.org), for cancer survivors using a mixed-methods approach. Formative research included a comprehensive literature review and four focus groups on website preferences with diagnosis-diverse cancer survivors (N = 17). Their feedback informed a web adaptation of a telephone counseling and mailed-print lifestyle intervention previously found effective for cancer survivors. The resulting web-based intervention was examined in a 3-week, single-arm trial among 41 cancer survivors. Assessments of physical activity, diet, body weight, and knowledge related to exercise and diet guidelines for cancer survivors occurred at baseline and 3 weeks later, along with exit interviews. Themes from focus groups indicated cancer survivors’ desire for easy-to-use, interactive web-based platforms to access credible diet and exercise information. The study sample was recruited within 12 months, and study retention was high (85.4%). Participants showed significant pre- to post-test improvements in diet and exercise knowledge (t = 5.31, p <.0001) and physical activity (t = 2.40, p =.02). Improvements in body weight and some dietary components (red meat, alcohol) were observed, but did not reach statistical significance. Results support the feasibility and acceptability of SurvivorSHINE. The significant increases in healthy lifestyle knowledge and physical activity found in the current study are promising, but a larger, randomized-controlled trial is needed to determine efficacy.