Abstract Background Pancreatic pseudocysts requiring treatment for pain or obstructive symptoms may be drained by percutaneous or open surgical techniques. Endoscopic drainage has been reported in a few small series with short-term follow-up. The aim of this study was to determine the indications and success rates of transmural endoscopic drainage procedures. Methods All patients who presented over a 2-year period to a tertiary referral centre with pancreatic pseudocysts were included in the study. Endoscopic drainage was attempted using a side-viewing endoscope in patients with pseudocysts bulging into the stomach or duodenal lumen. Outcome measures were successful drainage of the pseudocyst, complication and recurrence rates. Results Sixty-six patients presented with pseudocysts of which 34 were thought to be suitable for endoscopic drainage. Twenty-four were successfully drained. Failures were associated with thick-walled pseudocysts (greater than 1 cm), location in the tail of the pancreas and pseudocysts associated with acute necrotizing pancreatitis. There were no deaths and only one patient required emergency surgery for bleeding from the pseudocyst wall. There were three recurrences with a median of 41 (interquartile range 3–51) months of follow-up, two of which were successfully redrained endoscopically. The long-term success rate of the initial procedure was 62 per cent. Conclusion Transmural endoscopic drainage is a safe procedure with minimal complications, although surgical facilities must be available. It should be the procedure of choice for pseudocysts associated with chronic pancreatitis or trauma, with a wall thickness of less than 1 cm and a visible bulge into the gastrointestinal lumen. Applying these criteria to the 66 consecutive patients with pancreatic pseudocysts presenting over this initial 2-year study period, 26 (39 per cent) were suitable for the procedure. Technical success was achieved in 24 of the 26 patients and long-term success in 22.