Human genome epidemiology involves the application of genetic technology to assess the impact of variations at the DNA level on health and disease. Recent developments in molecular biology allow epidemiologists to use biomarkers to determine an individuals predisposition to disease and to detect disease at an early stage. Moreover, advances in genomics and proteomics could play a central role in research into disease prediction and prevention. Large scale population-based cohort prospective studies offer the most comprehensive approach to the delineation of gene function, the effects of the environment, and their interactions. The Korean Multi-center Cancer Cohort (KMCC), under construction since 1993, is the first multi-center prospective cohort to identify risk factors for cancer in Korea. Data on general lifestyle, physical activity, diet, reproductive factors, and agricultural exposure are obtained through direct interview using a structured questionnaire. Anthropometric measurements and clinical laboratory findings are also collected using a web-based data entry system. Moreover, biological materials have been banked [blood (serum, plasma, buffy coat, packed erythrocytes) is stored at -70 degrees C and urine at -20 degrees C] for future analysis. Several other cohorts including the Korean National Cancer Center (KNCC) Cohort, the Korean Health Examinees (KOEX) Cohort, the Korean Health and Genome Epidemiologic Study (KHGES), and the Yang Pyeong Cohort have also been launched since the KMCC cohort was initiated. Even though these cohorts have collected similar data and biospecimen, questionnaires and protocols used have not been standardized. However, these cohort studies are of increased scope and have been designed to detect risk factors for cardiovascular disease, metabolic syndrome, and cancer. Subjects have been followed up actively by health personnel in different regions and by using record linkages with the central cancer registry, and the national death certificate and national health insurance claim databases. As of August 2004, the total number of subjects enrolled in all cohorts with archived biologic specimens was around 80,000. A new genomic cohort has been launched since 2001 in Korea, for which the target number of subjects is 250,000 men and women over the next 5 years. This article describes the goals and the designs of each of the above-mentioned cohorts.