Background: Sedentary behavior is emerging as an important field of scientific enquiry for cancer survivorship. The posttreatment period is associated with prolonged recovery, deterioration in quality of life, disability, poor mental health, and reduced productivity. Exercise in cancer survivors has been linked with reduced fatigue, improved functional outcomes, and improved survival. Purpose: To evaluate the effect of a surgical cancer prehabilitation program on the long-term physical and psychological health in a cohort of patients undergoing surgery for esophagogastric cancer. Methods: The PREPARE program is a multimodal cancer prehabilitation program. All patients who underwent curative esophagogastric cancer surgery and completed the PREPARE program were included in the study. Weekly activity scores, self-efficacy, exercise testing, and hand grip strength were assessed. Results: A total of 39 patients met the eligibility criteria. At baseline, 31% of patients were active, 13% were moderately active, and 56% were insufficiently active. At follow-up, 44% of patients were active, 13% were moderately active, and 44% were insufficiently active. There was a significant increase in leisure score index (P= .048, z= -1.981), <(V)over dot>o(2max,) mL.kg(-1).min(-1) (P <= .01), and hand grip strength (P <= .01) from baseline to follow-up. There was no change in self-efficacy through baseline to follow-up. Limitations: Improvements in the postoperative period could be expected as part of recovery. The absence of a control group makes this difficult to establish. Conclusion: Starting prehabilitation at the time of diagnosis leads to sustained confidence and improved activity and exercise levels in the posttreatment period.