The indications for drainage of collections include the presence of infection, mass effect on adjacent organs, persis­tent symptoms, and large collections >5cm in size that per­sist for more than 6weeks [7]. The mass effect may be in the form of gastric outlet obstruction, biliary obstruction, ure­teric obstruction, and portal hypertension. As far as possible, the retroperitoneal route is preferred for the drainage of peri­pancreatic collections, as the same tract can be used for endoscopic or minimally invasive necrosectomy (Fig.34.3). Other approaches that can be used are transperitoneal through the anterior abdominal wall and transhepatic and transgastric routes. CT guidance is required when a retro­peritoneal approach is used, while large collections reaching up to the anterior abdominal wall can be targeted under USG guidance if the patient is not hemodynamically stable enough to be shifted for CT-guided drainage. The transverse colon should be avoided while draining the collection via the ante­rior route due to the risk of the transgression of colonic bac­teria into the collection. While infected collections need to be drained immediately, sterile uid collections can be drained after 3–4weeks once they liquefy. 10–12F pigtail catheters can be used for the initial drainage. They can be sequentially upgraded to 20–24F if adequate drainage is not obtained with smaller bore catheters. Malecot catheter has wider holes that help in better drainage of thick necrotic debris.