Purpose: Deciding whether or not surgery should be performed for elderly patients is sometimes difficult. This study examined the prognosis of patients ≥ 80 years old with gastric cancer who underwent surgery or not. Methods: The medical records of 111 patients who underwent surgery (surgery group) and 35 who received best supportive care (BSC group) were retrospectively reviewed, excluding those with clinical stage IVB disease, those with a performance status of 4, and those who underwent endoscopic submucosal dissection. The overall survival was compared between the two groups. Results: The patients in the BSC group were significantly older and had worse performance status scores, worse physiological scores, and lower prognostic nutritional indexes than those in the surgery group. The patients in the surgery group showed a significantly better survival than those in the BSC group (median survival time, 38.9 vs. 11.4 months; p = 0.01) even after propensity score matching. In the subgroups of patients ≥ 90 years old and those with a performance status of 3, no marked difference in the survival between the 2 groups was observed. Conclusions: Surgery imbued a survival benefit to elderly gastric cancer patients, except for those ≥ 90 years old and those with a performance status of ≥ 3. The surgical indication of patients ≥ 90 years old and those with a performance status of ≥ 3 requires careful deliberation. [ABSTRACT FROM AUTHOR]