AIM: To explore the implications of underlying diseases in treatment of pancreatic pseudocysts (PPC). METHODS: Clinical data of 73 cases of pancreatic pseudocyst treated in a 12-year period were reviewed comprehensively. Pancreatic pseudocysts were classified according to the etiological criteria proposed by D’Egidio. The correlation between the etiological classification, measure of treatment and clinical outcome of the patients was analyzed. RESULTS: According to the etiological criteria proposed by D’Egidio, 73 patients were divided into three groups. Group I was comprised of 37 patients with type I pseudocyst, percutaneous drainage was successful in the majority (9/11, 82%) while external or internal drainage was not satisfactory with a low success rate (8/16, 50%). Group II was comprised of 24 patients with type II pseudocyst, and internal drainage was curative for most of the cases (11/12, 92%), but the success rate of percutaneous or external drainage was unacceptably low (4/9, 44%). Group III consisted of 12 patients with type III pseudocyst. Internal drainage or pancreatic resection performed in 10 of these patients produced a curative rate of 80% (8/10) with the correction of the ductal pathology as a prerequisite. CONCLUSION: The classification of pancreatic pseudocyst based on its underlying diseases is meaningful for its management. Awareness of the underlying diseases of pancreatic pseudocyst and detection of the ductal pathology in type II and III pancreatic pseudocysts with endoscopic retrograde cholangiopancreatography may help make better decisions of treatment to reduce the rate of complications and recurrence. AIM: To explore the implications of underlying diseases in treatment of pancreatic pseudocysts (PPC). METHODS: Clinical data of 73 cases of pancreatic pseudocyst treated in a 12-year period were reviewed comprehensively. Pancreatic pseudocysts were classified according to the etiological criteria proposed by D’Egidio. The correlation between the etiological classification, measure of treatment and clinical outcome of the patients was analyzed. RESULTS: According to the etiological criteria proposed by D’Egidio, 73 patients were divided into three groups. Group I was comprised of 37 patients with type I pseudocyst, percutaneous drainage was successful in the majority (9/11, 82%) while external or internal drainage was not satisfactory with a low success rate (8/16, 50%). with type II pseudocyst, and internal drainage was curative for most of the cases (11/12, 92%), but the success rate of percutaneous or external drainage was unacceptably low (4/9, 44%). Group III consisted of 12 patients with type III pseudocyst. Internal drainage or pancreatic resection performed in 10 of these patients produced a curative rate of 80% (8/10) with the correction of the ductal pathology as a prerequisite. CONCLUSION : The classification of pancreatic pseudocyst based on its underlying diseases is meaningful for its management. Awareness of the underlying diseases of pancreatic pseudocyst and detection of the ductal pathology in type II and III pancreatic pseudocysts with endoscopic retrograde cholangiopancreatography may help make better decisions of treatment to reduce the rate of complications and recurrence