Colorectal cancer is one of the most steeply increasing malignancies in Korea. Among 398,824 new patients recorded by the Korea Central Cancer Registry between 2003 and 2005, 47,915 cases involved colorectal cancers, accounting for 12.0 % of all malignancies. In 2002, total number of colorectal cancer cases had accounted for 11.2 % of all malignancies. Hereditary syndromes are the source of approximately 5% to 15% of overall colorectal cancer cases. Hereditary colorectal cancers are divided into two types: hereditary nonpolyposis colorectal cancer (HNPCC), and cancers associated with hereditary colorectal polyposis, including familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome, juvenile polyposis, and the recently reported hMutYH (MYH)-associated polyposis (MAP). Hereditary colorectal cancers have unique clinical features distinct from sporadic cancer because these are due to germline mutations of the causative genes; (i) early age-of-onset of cancer, (ii) frequent association with synchronous or metachronous tumors, (iii) frequent association with extracolonic manifestations. The management strategy for patients with hereditary colorectal cancer is quite different from that for sporadic cancer. Furthermore, screening, genetic counseling, and surveillance for at-risk familial member are also important. A well-organized registry can plays a central role in the surveillance and management of families affected by hereditary colorectal cancers. Here, we discuss each type of hereditary colorectal cancer, focusing on the clinical and genetic characteristics, management, genetic screening, and surveillance.