To examine the prognostic value of claudin 18.2 (CLDN18.2) and human epidermal growth factor receptor-2 (HER-2) expression in patients with resected pancreatic ductal adenocarcinoma (PDAC). This study enrolled patients who underwent surgery and were diagnosed with PDAC at Suleyman Demirel University Hospital, Turkey between 2015 and 2019. Sixty-eight patients with resected PDAC treated at a medical oncology clinic were assessed. All patients were over the age of 18 years, underwent follow-up and treatment in our unit, and had pathology slides that we could access. Clinicopathological data were obtained from medical files, including the patients' age, sex, pathological parameters, and clinical stage according to the Eighth International Union against Cancer/American Joint Committee on Cancer. Patient survival and the period from the date of diagnosis to death were assessed in the follow-up data. There was no statistically significant difference between CLDN18.2 and HER-2 expression scores for samples and patient clinicopathological characteristics. No HER-2 expression scores of ≥2 were found in the samples. Only 25% (n = 17) of the samples had HER-2 expression scores of +1. CLDN18.2 expression was detected in 54.4% (n = 37) of the patient samples. CLDN18.2 expression scores were +1 in 30.8% (n = 21) of the patient samples, +2 in 16.2% (n = 11), and +3 in 7.4% (n = 5). When CLDN18.2 and HER-2 expression were compared, a statistically significant difference and moderate positive correlation were observed. No significant relationship between HER-2 expression and survival was observed in the survival analysis of PDAC patients; however, high CLDN18.2 expression was related to longer overall survival. Our study is the third to research CLDN18.2 expression in PDAC. HER-2 expression is low and CLDN18.2 expression is high in patients with PDAC. HER-2 expression is not related to overall survival but CLDN18.2 is related and may be used as a prognostic marker in patients with PDAC.