A pseudocyst is a persisting localized pancreatic or peripancreatic fluid collection that is generally rich in pancreatic enzymes. It lacks a true wall and is surrounded by a fibrous tissue wall without true epithelialization (Bradley 1993). Pseudocysts are thought to form as a result of a leak from a disrupted pancreatic duct, or more commonly a side branch, and are frequently asymptomatic. They can be sequelae of severe acute pancreatitis or of chronic pancreatitis. Symptomatic pseudocysts can be managed endoscopically, radiologically or surgically (Boerma et al. 2000). Pancreatic necrosis and cystic neoplasms can cause diagnostic dilemmas. This chapter focuses on the endoscopic management of pancreatic pseudocysts.