One hundred patients with documented pancreatic pseudocysts who underwent surgical drainage are reported on. Accurate assessment of the size and location of the pseudocyst using ultrasonography, endoscopic retrograde cholangiopancreatography, angiography, and upper gastrointestinal roentgenography is essential. After diagnosis, the next 4 to 7 weeks is a critical period, after which surgical intervention becomes mandatory if the cyst has not resolved. This period between diagnosis and operation is hazardous and demands close clinical follow-up. When oepration is required, the preferred procedure continues to be internal drainage because it is associated with less morbidity and a lower mortality. However, external drainage appears to be a suitable second choice. Fewer than 10 per cent of the patients in this series who underwent external drainage developed fistulas, and the overall rate of late morbidity was acceptable.