Endoscopic ultrasonography-guided fine-needle aspiration(EUS-FNA) has been applied to pancreaticobiliary lesions since the 1990 s and is in widespread use throughout the world today. We used this method to confirm the pathological evidence of the pancreaticobiliary lesions and to perform suitable therapies. Complications of EUS-FNA are quite rare, but some of them are severe. Operators should master conventional EUS observation and experience a minimum of 20-30 cases of supervised EUS-FNA on non-pancreatic and pancreatic lesions before attempting solo EUSFNA. Studies conducted on pancreaticobiliary EUSFNA have focused on selection of suitable instruments(e.g., needle selection) and sampling techniques(e.g., fanning method, suction level, with or without a stylet, optimum number of passes). Today, the diagnostic ability of EUS-FNA is still improving; the detection of pancreatic cancer(PC) currently has a sensitivity of 90%-95% and specificity of 95%-100%. In addition to PC, a variety of rare pancreatic tumors can be discriminated by conducting immunohistochemistry on the FNA materials. A flexible, large caliber needle has been used to obtain a large piece of tissue, which can provide sufficient histological information to be helpful in classifying benign pancreatic lesions. EUSFNA can supply high diagnostic yields even for biliary lesions or peri-pancreaticobiliary lymph nodes. This review focuses on the clinical aspects of EUS-FNA in the pancreaticobiliary field, with the aim of providing information that can enable more accurate and efficient diagnosis. Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has been applied to pancreaticobiliary lesions since the 1990 s and is in widespread use the world today. We used this method to confirm the pathological evidence of the pancreaticobiliary lesions and to perform suitable Therapies of EUS-FNA are quite rare, but some of them are severe. Operators should master conventional EUS observation and experience a minimum of 20-30 cases of supervised EUS-FNA on non-pancreatic and pancreatic lesions before attempting solo EUSFNA. Studies conducted on pancreaticobiliary EUSFNA have focused on selection of suitable instruments (eg, needle selection) and sampling techniques (eg, fanning method, suction level, with or without a stylet, optimum number of passes). Today, the diagnostic ability of EUS- FNA is still improving; the detection of pancreatic cancer (PC) currently has a sensitivity of 90% -95% and specificity of 95% -100%. In addition to PC, a variety of rare pancreatic tumors can be discriminated by conducting immunohistochemistry on the FNA materials. A flexible, large caliber needle has been used to obtain large pieces of tissue, which can provide sufficient histological information to be helpful; classifying benign pancreatic lesions. EUSFNA can supply high diagnostic yield even for biliary lesions or peri-pancreaticobiliary lymph nodes. This review focuses on the clinical aspects of EUS-FNA in the pancreaticobiliary field, with the aim of providing information that can enable more accurate and efficient diagnosis.