Splenic pseudocyst is a rare disease associated with chronic and acute pancreatitis splenic pseudocyst is treated by distal pancreatectomy and splenectomy. A 47-year old woman with a 10-year history of alcohol abuse presented with epigastric and left upper quadrant pain of 3 days duration. Abdominal CT showed a 4.0×4.5 cm sized cystic lesion in the tail of the pancreas. Analgesics was administrated for the relief of abdominal pain. On the 4th hospital day, the patient complained more of left upper quadrant pain, so we took follow up CT scans. On follow up CT, one large splenic pseudocyst with size of 9.5×4.5×10.0 cm was noted. The patient was treated conservatively by percutaneous catheter drainage and discharged on the 13th hospital day. This case is the first case report of splenic pseudocyst treated conservatively, not by surgery in Korea.