In patients with gastric carcinomas, the role of the alteration of mucin expression in overall survival has been a matter of some speculation, but few studies have been reported. The aim of our study was to determine the relationship between MUC1, MUC2, and MUC5AC expression and patient survival, with a secondary aim designed to investigate the alteration of MUC expression within various clinicopathologic parameters. Forty-four specimens from gastric carcinoma patients were immunohistochemically evaluated using the monoclonal antibodies for MUC1 (EMA, clone E29), MUC2 (CCP58), and MUC5AC (human gastric mucin, clone 45M1). MUC1 expression increased in gastric carcinoma. MUC1 positivity was determined to be statistically significant, with poor clinicopathological parameters and decreased long-term survival. MUC5AC expression decreased in gastric carcinoma. In addition, patients with MUC5AC-positive tumors also had poor clinicopathological parameters and showed shorter survival than those with MUC5AC-negative tumors. MUC2 expression was not significantly associated with patient survival. We confirmed that the expression of mucins is associated with characteristics of differentiation in gastric carcinoma. Poor patient outcomes were seen in gastric carcinomas with MUC1 mucin expression and MUC5AC positivity.