PROJECT SUMMARY Identifying modifiable prenatal and early life risk factors is crucial for developing strategies to prevent childhood asthma. While individual birth cohort studies have identified several asthma-related genetic, personal and environmental risk factors, these studies were mainly limited to homogeneous cohorts and modest sample sizes. Pooling data from multiple diverse cohorts could address these limitations. Based on the momentum and accomplishments of collaborative multicenter research in the Children’s Respiratory and Environmental Workgroup (CREW), we propose establishing a children's allergy and asthma data hub to ensure enduring access for the scientific community to allergy and asthma birth cohort data. The proposed Children's Allergy and Asthma Data Repository (CADRE) will leverage hundreds of millions of NIH dollars invested in conducting allergy and asthma cohort studies by pooling and harmonizing these data for future collaborative studies. We propose to initiate CADRE using CREW’s existing data set and data-sharing procedures and then expand this critical resource to invite, facilitate and accommodate broad participation from the scientific community. The CADRE data repository will invite collaboration and ensure ease of use by providing value-added services to facilitate data accessibility, usability, harmonization and interpretation. To accomplish these goals, we propose three specific aims. First, we will expand the CREW repository of birth and infant cohorts’ data focused on identifying risk factors, clinical phenotypes and natural history of childhood allergic diseases and asthma by collecting more data from the original cohorts and by recruiting new collaborators and cohorts to contribute data to the repository. Second, we will develop the CADRE data collaboration platform as a foundation for a national data ecosystem for secure integrative allergic diseases and asthma research. Third, we will establish the administrative infrastructure to develop, refine and establish an ethical and compliant data-sharing and governance process for the acquisition, linkage, usage, and analysis of multidimensional data containing protected health information (PHI) and secure export non-PHI results to investigative teams. Establishing the CADRE data repository will preserve, pool, and harmonize the precious and far-reaching data sets of US childhood asthma and allergy cohorts. CADRE will develop secure procedures to facilitate investigators' access and utilization of these comprehensive and irreplaceable data for collaborative studies while simultaneously protecting the privacy of research participants.