 EUS-guided fine needle aspiration FNA is a major diagnostic tool in the patient with pancreatic mass with high specificity, specificity and accuracy. However FNA with small needle has sometimes failed in acquisition of tissue due to small caliber. To overcome this limitation, newly designed ProCore needle was developed and flexible 22 and 25 gauge ProCore needles were frequently used. However there was no comparative study of the efficacy and accuracy between 22 and 25 gauge ProCore needle yet. 