Background: In the past, various prognostic factors in pancreatic ductal carcinoma (PDAC) have been identified, and there found to be not only tumor-specific clinicopathological factors but also individual patient characteristics. In particular, weight loss, muscle wasting and cachexia are hallmarks of PDAC that may be associated with depletion of both skeletal muscle and adipose tissue. Most notably, sarcopenia is defined to be degenerative loss of skeletal muscle mass that is quantifiable using cross sectional imaging computed tomography (CT) by measurement of psoas area and the muscle’s density. Furthermore, visceral adipose tissue loss also has been reported to associate with a poor survival among patients with PDAC. Methods: A total of 265 patients who underwent curative surgery for PDAC were examined in this study. The total skeletal muscle and fat tissue areas were evaluated in a single image obtained at the third lumber vertebra during a preoperative computed tomography (CT) scan. The patients were assigned to either the sarcopenia or non-sarcopenia group based on their skeletal muscle index (SMI) and classified into high visceral fat area (H-VFA) or low VFA (L-VFA) groups. The association of clinicopathological features and prognosis with the body composition were statistically analyzed. Results: There were 170 patients (64.2%) with sarcopenia. The median survival time (MST) was 23.7 months for sarcopenia patients and 25.8 months for patients without sarcopenia. The MST was 24.4 months for H-VFA patients and 25.8 months for L-VFA patients. However, sarcopenia patients with BMI ≥ 22 exhibited significantly poorer survival than patients without sarcopenia (MST: 19.2 vs. 35.4 months, P = 0.025). There was a significant difference between patients with and without sarcopenia who did not receive chemotherapy (5-year survival rate: 0% vs. 68.3%, P = 0.003). The multivariate analysis revealed that tumor size, positive dissected peripancreatic tissue margin, and sarcopenia were independent prognostic factors. Conclusions: Sarcopenia is an independent prognostic factor in PDAC patients with a BMI ≥ 22. Therefore, evaluating skeletal muscle mass may be a simple and useful approach for predicting patient prognosis.