Norwegian cohorts have been set up to understand both the etiology of disease and the determinants of progression of disease. Three major cohorts, the Tromsø cohort, the Nord-Trøndelag Health study (HUNT) and the Norwegian Mother and Child Cohort Study (M oBa) have a wealth of exposure information as well as phenotypes and disease endpoints. We now propose to genotype random subjects and triads from these three cohorts for the benefit of a large number of later subprojects. We suggest to use a new versatil e chip, the Illumina Human Core Chip (combochip) and to perform the genotyping on a national platform. We will also use newly established Norwegian infrastructure for safe storage and data analysis. The coordinated use of these resources as well as other previously genotyped samples from the same cohorts will enhance productivity and open for important new results on the path to increased understanding of basic disease mechanisms with the ultimate aim of better prevention and personalized medicine.