AIM: To study the clinical characteristics of hereditarynonpolyposis colorectal cancer (HNPCC) in the Chinesepopulation and discuss the identification and managementof the patients with HNPCC.METHODS: A series of 140 patients with colorectal cancers(CRC) and HNPCC associated tumors from 30 families fulfillingthe Amsterdam criteria were analyzed.RESULTS: A total of 118 patients had CRC. Average age atdiagnosis of the first CRC was 45.7 years, 56.8 % and 23.4 %of the first CRC were located proximal to the splenic flexureand in the rectum respectively. Twenty-three (19.5 %) hadsynchronous and metachronous CRC. Twenty-seven patientswere found to have extracolonic tumors. Gastric carcinomawas the most common tumor type in our series (44.4 %).CONCLUSION: The frequency of HNPCC was 2.6 % in ourseries of patients. The main features are an excess of earlyonset with a propensity to involve the proximal colon, andhigh frequency of multiple foci. Management and surveillancefor these patients should be different from sporadic CRC.Contrary to American and European reports, gastric cancerseems more frequent than endometrial cancer in Chinese.It is necessary to formulate a new HNPCC criterion forChinese patients.