Lipohyperplasia of the ileocecal valve is a rarely diagnosed lesion of unknown etiology and uncertain significance, which is characterized by diffuse infiltration of mature adipose tissue in the submucosal layer of the ileocecal valve. For endoscopists and radiologists, it has often remained difficult to make a distinction from malignant neoplasia. We describe two cases of lipohyperplasia of the ileocecal valve, all histopathologically diagnosed after major surgery. Case 1 was a 44-year-old male with abdominal distention and epigastric discomfort for two years. Preoperatively villous adenoma with suspicious cancerous changes in the ascending colon was suspected and a right hemicolectomy was performed. Grossly, a tongue-like projection of the enlarged ileocecal valve up to 3*1.5cm was featured microscopically with heavy deposition of mature fat tissue in the subucosal layer. Case 2 was a 33-year-old female with an episode of melena. After radiologic and endoscopic study for Behcets enterocolitis, the right hemicolectomy was performed. Grossly, the ileocecal valve was enlarged up to 3cm and the histologic feature was similar to that of the first case. Through these two cases, we made the conclusion that an appropriate understanding of ileocecal valvular hyperplasia seems to be the first step to make a preoperative histologic diagnosis and prevent oversurgery. (Korean J Gastroenterol 1997; 30:541-546)