Purpose: Clinical treatment of gastrointestinal neoplasms in patients with severe coronary stenosis is difficult, and it remains controversial to perform staged or simultaneous surgeries. The purpose of this study was to retrospectively analyze the feasibility and indications for simultaneous gastrointestinal tumor resection and off-pump coronary artery bypass (OPCAB) graft surgery. Methods: Data collected from a total of five patients, including three patients with gastric cancer and two patients with colorectal cancer, who underwent simultaneous radical cancer resection and OPCAB between September 2010 and October 2019, were retrospectively analyzed. Among these patients, one had an incomplete colonic obstruction. All patients had severe coronary stenosis, and one experienced acute heart failure before surgery. OPCAB was performed first, followed by the radical cancer resection. Results: All five patients were discharged from hospital without perioperative death, major cardiovascular events or anastomotic leakage. The mean postoperative hospital stay was 9.4 days. One patient experienced slight gastrointestinal bleeding after surgery, which improved with conservative treatment. After a mean follow-up of 39 months, two patients with gastric cancer died from tumor metastasis at 28 months and 37 months, while the remaining three patients did not have tumor recurrence or metastasis. None of the patients experienced myocardial ischemia. Conclusion: It is safe and feasible to perform simultaneous OPCAB and gastrointestinal surgeries on the premise of strictly controlling the indications for patients with gastrointestinal tumors complicated with severe coronary artery stenosis.