Claudin-18.2 (CLDN18.2) is specifically expressed in pancreatic precancerous lesions and pancreatic ductal adenocarcinoma (PDAC). We assessed clinical characteristics of patients with CLDN18.2 overexpressing pancreatic cancer to identify patients who might benefit from CLDN18 targeted treatment. 130 patients with surgically resected PDAC were investigated the immunohistochemical expression of claudin-18 (CLDN18). The CLDN18 staining intensities (0-3+) and relative proportion of positive tumor cells were analyzed by two independent raters. Tumor as positive for CLDN18 expression was defined as ≥80% of tumor cells with 2+ or 3+ staining intensity on CLDN18 immunohistochemical assay. Positive CLDN18 expression was present in 41/130 (31.5%) surgically resected PDAC and the relative proportion of positive tumor cells and the staining intensity were directly correlated (p < 0.001). Positive CLDN18 expression was significantly associated with well-differentiated tumor (p<0.001) and less regional node involvement (p=0.045). The positive CLDN18 expressing group showed no statistical difference in median overall survival (17.4 months vs. 20.6 months, p=0.770) compared to negative CLDN18 expressing group. Distant nodal metastasis was more frequent in positive CLDN18 expressing group (p=0.011). CLDN18 is frequently expressed in PDAC, and high CLDN18 expressing PDAC showed some different clinicopathologic characteristics. High CLDN18 expression was not associated with prognosis in patients with surgically resected PDAC.