Colorectal cancer is the third leading cause of cancer and the second leading cause of cancer death in the United States. About 130,000 new cases are diagnosed each year in North America, and 56,600 persons die annually from this disease. Approximately 5% of patients with colorectal cancer have clearly defined inherited syndromes such as familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. These conditions are well described both genetically and phenotypically, and are characterized by autosomal dominant inheritance, high penetrance, and high risk of colorectal cancer. We review the current recommendations for the diagnosis and management of these two hereditary forms of colorectal cancer.