To assess the prognostic significance of postoperative changes in immune status represented by total lymphocyte count (TLC) and neutrophil-to-lymphocyte ratio (NLR) in resectable pancreatic cancer. Patients who underwent curative pancreatectomy for pancreatic adenocarcinoma were divided into high and low groups according to cut-off values of TLC, and NLR measured preoperatively, immediately after surgery, and 1 or 6 months after surgery. Oncologic outcomes were compared between the two groups at different times, and prognostic roles of TLC and NLR were evaluated. Of 193 patients, the median follow-up time was 22 months, and median survival was 18 months. Their immunologic status deteriorated within 3 to 4 days after the operation and recovered after that. At 1 and 6 months postoperatively, overall survival rates were significantly lower in the group with high NLR (>2.535 and >3.21, respectively) and low TLC (<1.66 × 109 and <1.62 × 109 /L, respectively). In multiple regression analyses, elevated NLR at postoperative 1 and 6 months and decreased TLC at postoperative 1 month were significant prognosis predictors. Changes in immune status such as decreased TLC and elevated NLR at postoperative 1 and 6 months are effective prognostic predictors after curative pancreatectomy in patients with pancreatic adenocarcinoma. © 2019 Wiley Periodicals, Inc.