Because echoendoscopes equipped with a linear or convex array visualize the needle protruding from its channel, they are used in ultrasound-guided aspiration and therapy. Recently, endoscopic ultrasound (EUS)-guided aspiration has been the interventional EUS method of choice in an array of treatments. EUS-guided fine-needle aspiration is used in the differential diagnosis and staging of pancreatic tumors, where the pancreatic tissue or its surrounding lymph nodes are punctured through the gastrointestinal wall. In EUS-guided celiac plexus neurolysis, injecting ethanol around the celiac artery through the gastric body to block pain in patients with pancreatic carcinoma is considered safer and more accurate than ordinary celiac plexus neurolysis. EUS is valuable in transmural pseudocyst drainage. Because an echoendoscope equipped with a linear or convex array visualizes the large vessels, vessels lying between the needle and the pseudocyst can be avoided, preventing bleeding that might otherwise result. Other reports cover such uses as EUS-guided stenting by puncturing the bile duct or pancreatic duct after unsuccessful transpapillary stenting by ERCP. Further application of interventional EUS to other treatments is anticipated.