To clarify the prognostic value of the postoperative blood neutrophil-to-lymphocyte ratio (NLR) in patients undergoing pancreatectomy for pancreatic carcinoma (PAC). A high preoperative NLR has been reported to be a predictor of poor survival in patients with various cancers including PAC. However, it has not been extensively examined in postoperative NLR after pancreatectomy for PAC. This retrospective study enrolled 86 patients who underwent pancreatectomy without preoperative therapy for PAC from 2005 to 2013. Clinicopathological parameters, including postoperative NLR, were evaluated to identify predictors of the overall and recurrence-free survival of patients after pancreatectomy. Univariate and multivariate analyses were performed, using the Cox proportional hazards model. Univariate and multivariate analyses showed that postoperative NLR at one month was an independent prognostic factor in the overall and recurrence-free survival of patients. The 3-year survival rate after pancreatectomy was as follows: 33.9 per cent in patients with a postoperative NLR of less than 3.0 at one month; and 7.3 per cent in those with a postoperative NLR of 3.0 or more at one month (P < 0.001). The overall survival rate after pancreatectomy in the NLR at one month ≥3.0 group was significantly lower than in the NLR at one month <3.0 group: one year, 42.6 versus 81.9 per cent; three year, 7.3 versus 33.9 per cent (P < 0.001). The results of the study suggest that the postoperative NLR at one month is an independent predictor of survival after pancreatectomy in patients with PAC.