Colorectal cancer (CRC) is a multifactorial disease, where both the environment and genetics play a role. It is estimated that approximately 35% of CRCs have a potentially identifiable genetic cause. Well-known and highly penetrant genetic causes make up less than 5% of all CRC, and leave many families not explained by known predisposing genes/mutations. Low penetrant alleles have also been thought to modify the risk of CRC. Linkage studies have been successful in discovering and localizing highly penetrant genes in CRC and risk loci has become possible to discover performing genome wide association studies (GWAS). In this study we have analyzed families with CRC where individuals with CRC as well as individuals with premalignant lesions, adenomas, were codes as affected. In total 600 individuals in 121 families were included in the study. In total three genomic regions were found with suggestive linkage located at 4p16.3, 6p24.3 and 10p14. These regions were further studied using sequencing analysis and association studies using haplotypes.