The Population Research Core (PopRC) is a centralized resource dedicated to the needs of the Holden Comprehensive Cancer Center (HCCC) in the domain of population science. Quality epidemiology support promotes strong observational study designs and data collection and data curation methods. The PopRC provides this support in close collaboration with HCCC members and the Tissue Procurement Core, Molecular Epidemiology Resource, and Biostatistics Core. The primary resources of the PopRC are its scientific personnel and its curated and annotated population-based data. The PopRC provides HCCC members with guidance and assistance in accessing and using large databases of cancer patient data that include SEER- Medicare, SEER-Medicare Health Outcomes Study (MHOS), enhanced unlinked SEER research dataset, Iowa driver's license database, the Iowa Mortality database, the Greater Plains Collaborative, and others. A number of these resources are unique to the HCCC catchment area (the state of Iowa). In addition to database research activities, the PopRC supports personnel with a wide range of expertise including population study designs, field research methods and tools, and biospecimens linked to clinical registries. PopRC personnel collaborate closely with the Biostatistics Core on analytic plans and data analysis of population studies, and with the Tissue Procurement Core and Molecular Epidemiology Resource to ensure efficient and effective coordinated access for investigators to biospecimens. The PopRC collaborates with the Tissue Procurement Core by providing samples from the Iowa Residual Tissue Repository and Virtual Tissue Repository that are linked to SEER data. The PopRC supports HCCC members from all four research programs, with 62 percent of the users of the facility being HCCC members. Projects commonly involve collaborations of HCCC epidemiologists with clinician and basic scientists across the HCCC and from other academic institutions. Plans in the upcoming funding period include enhancing access by HCCC members to robust clinical data linked to unique tissue resources. In summary, the PopRC is a comprehensive, collaborative and integrated resource that is vital to the HCCC.