Background: A time interval between diagnosis and surgery for gastric cancer is necessary, although its impact on survival remains controversial. We evaluated the impact of preoperative time interval on survival in gastric cancer patients. Methods: We enrolled 332 patients who underwent curative gastrectomy for clinical stage (cStage) I–III gastric cancer between 2012 and 2015. We separately analyzed early- (cStage I) and advanced-stage (cStages II and III) patients. Early-stage patients were divided according to preoperative time interval: short (≤ 42 days) and long (> 42 days) groups. Advanced-stage patients were also divided into short (≤ 21 days) and long (> 21 days) groups. We compared the survival between the short and long groups in early- and advanced-stage patients. Results: The median preoperative time interval was 29 days, and no significant differences were found in patient characteristics between the short and long groups in early- and advanced-stage patients. In early-stage patients, the 5-year survival rates of the short and long groups were 86.5% and 88.4%, respectively (P = 0.917). In advanced-stage patients, the 5-year survival rates were 72.1% and 70.0%, respectively (P = 0.552). In multivariate analysis, a longer time interval was not selected as an independent prognostic factor in early- and advanced-stage patients. Conclusions: In this study, survival difference was not found based upon preoperative time interval. The results do not affirm the delay of treatment without reason, however, imperative extension of preoperative time interval may be justified from the standpoint of long-term survival. [ABSTRACT FROM AUTHOR]