Families undergoing genetic counseling for an increased risk of cancer and where no disease gene is known are being included in our ongoing studies. We have performed many studies to rule out possible candidate genes. Families without known mutations have been recruited to our linkage and association studies. We have in total identified more than 1000 families without mutations in known genes and many of those families have been included in studies. We have ongoing studies in familial colorectal cancer and familial breast cancer and we are looking for new cancer syndromes. We also use large clinical materials for testing the hypothesis of cancer as a complex disease. Our results are implemented into clinical praxis. We have studied effects of genetic counseling and genetic testing and surveillance in cancer families and been able to demonstrate the usefulness of oncogenetic counseling and that it does not bring unwanted side effects of anxiety. We have also continued to improve the procedure of genetic cancer counseling, and to improve the procedure of genetic testing and to evaluate the surveillance program. We have also found that patients under surveillance tolerate this well and are aware of its importance.