Background/Aims: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA; EUS-FNA) allows for diagnostic tissue specimens from various regions to be analyzed. How-ever, diagnosing recurrent pancreaticobiliary cancer after surgery is sometimes difficult. We evaluated the efficacy of EUS-FNA in the diagnosis of local recurrence of pancreatico-biliary cancer and analyzed the factors associated with falsenegative results. Methods: Fifty-one consecutive patients who underwent EUS-FNA due to suspected recurrence of pancreaticobiliary cancer after surgery in an academic cen-ter were retrospectively analyzed. The criteria for EUS-FNA were a resected margin or remnant pancreas mass, round swollen lymph node (≥10 mm in diameter), and soft-tissue enhancement around a major artery. Patients with suspected liver metastasis or malignant ascites were excluded. Results: Thirty-nine of the 51 patients had pancreatic cancer; the remaining 12 had biliary cancer. The target sites for EUS-FNA were the soft tissue around a major artery (n=22, 43%), the resected margin or remnant pancreas (n=12, 24%), and the lymph nodes (n=17, 33%). The median size of the suspected recurrent lesions was 15 mm (range, 8 to 40 mm). The over-all sensitivity, specificity and accuracy of EUS-FNA for the diagnosis of recurrence was 84% (32/38), 100% (13/13), and 88% (45/51), respectively. FNA of the soft tissue around major arteries (odds ratio, 8.23; 95% confidence interval, 1.2 to 166.7; p=0.033) was significantly associated with a falsenegative diagnosis in the multivariate analysis. Conclusions EUS-FNA is useful for diagnosing recurrent cancer, even after pancreaticobiliary surgery. The diagnoses of recurrence at soft-tissue sites should be interpreted with caution.