Each year approximately 15,000 patients are diagnosed with colorectal cancer (CRC) in the Netherlands, of whom 5-10% are associated with a hereditary syndrome. To enable future research into hereditary CRC, we established a collaborative biobank for hereditary CRC in all eight University Medical Centers (UMCs) in the Netherlands in 2009. This Biobank Hereditary CRC is part of the Parelsnoer Institute (PSI), which is funded by the Dutch Federation of UMCs and the Dutch Government. Besides the multicenter collaboration, the multidisciplinary nature of this biobank - involving Gastroenterology, Genetics and Surgery - is essential for its functionality and value. Patients at increased risk of hereditary CRC and/or Polyposis, or with a proven germline mutation causing CRC and/or Polyposis are included. Both clinical data (demographic data, details on medical and family history, information on surveillance, endoscopy and surgery, results of microsatellite instability and molecular genetic tests) and biomaterial (DNA, plasma, serum and tissue) are collected in a standardized manner.