OBJECTIVE To summarize the experience with diagnosis and therapy of familial adenomatous polyposis (FAP). METHODS Thirteen patients with FAP who had undergone total colectomy were analyzed retrospectively. RESULTS In 5 patients with benign and 8 patients with malignant adenomatous polyposis, their average age at operation was 31.5 years (range 10 - 57), 25 years in benign patients and 36 years in malignant patients. Familial inherited histories were found in 8 patients in 6 families. Nineteen patients were determined in 6 families in 3 generations. Seven familial members died of colorectal cancer in 4 families. History lasted 2 - 20 years. The number of adenomatous polyposis was more than 100. All patients underwent total colectomy, ileostomy or anus-preserving surgery with or without ileal pouch. All patients without canceration survived. The longest one exceeded 25 years, but 3/8 patients with canceration developed metastasis of liver, brain and abdomen within 6 months after surgery. CONCLUSIONS FAP will turn to be cancer if not removed. Total colectomy or proctocolectomy should be performed before canceration. Total colectomy, preserving muscular sheath of the rectum after mucosectomy, ileal pouch-anal anastomosis may be the operative choice for FAP.