Aims: The objective of this study was to assess the significance of ulcer size for the survival of gastric cancer patients. Methods: A total of 260 patients with ulcerative gastric cancer who had undergone curative resection were reviewed. The diameter of the malignant ulcer was measured. Patients were divided into group U1 (≤3 cm) and group U2 (>3 cm) according to the diameter of the ulcer. The prognostic significance of ulcer size was assessed by uni- and multivariate analyses. Results: Patient survival was correlated with age, gender, tumor location, tumor size, ulcer size, serosal invasion, node involvement and synchronism distant metastasis. The 5-year overall survival rate in U1 patients was 84.3% as compared with 67.5% in U2 patients (p < 0.001), and the 5-year recurrence-free survival rates were 82.9% for group U1 and 62.5% for group U2 (p = 0.001). Multivariate analysis revealed that ulcer size is an independently significant predictive factor for survival rates (overall: hazard ratio 1.222, p = 0.003; recurrence-free: hazard ratio 1.205, p = 0.006). Conclusion: Ulcer size might be a potential indicator for advanced disease and the use of minimal local treatments must be considered carefully in larger ulcer size patients.