Purpose: Postoperative pancreatic fistula (POPF) is the most important factor affecting morbidity and mortality after pancreaticoduodenectomy (PD). Patients with a high controlling nutritional status (CONUT) score, which is used to assess nutritional status, are expected to have high morbidity rates. This study aimed to determine the usefulness of the CONUT score. Methods: Data from 97 consecutive cases of PD performed in the Department of Surgery of Iwakuni Clinical Center, from April 2008 to May 2018, were included. Preoperative patient data, including sex, age, and hypertension, and postoperative complication data were collected to analyze pancreatic fistula occurrence. Results: Of the 97 patients, 2 9 patients (29.8%) were diagnosed with POPF ≥ B, with 26 cases (26.8%) classified as grade B and 3 (3.1%) as grade C. The mortality rate was 2.1% (2 of 97). In the univariate analysis, a significant association was observed between POPF and the following factors: body mass index (BMI) ≥ 22 kg/m2, high CONUT score, nonpancreatic carcinoma, and CT attenuation values. In multivariate analysis, BMI ≥ 22 kg/m2 (odds ratio [OR], 6.16; P < 0.001), high CONUT score (OR, 3.77; P = 0.009), nonpancreatic carcinoma (OR, 5.72; P = 0.009), and CT attenuation values (late/early ratio) in the pancreas (OR, 9.07; P = 0.006) were independent risk factors for POPF. Conclusion Patients with a high CONUT score are at high risk of POPF. Further study correlating preoperative nutritional intervention with risk of POPF is necessary.