ABSTRACT This project represents Phase II of the Human Pangenome Project, a global high-quality resource of human genetic diversity. We aim to expand our collection of human reference genomes from 350 to 550 by prioritizing an additional 200 samples, employing advanced technology for accurate, telomere-to-telomere (T2T) genome sequencing, and ensuring the ethical handling of all research stages, ultimately supporting the broader genomics research community with an improved pangenome resource. In Aim 1, the Genomes Center will direct the selection of new samples from prospective recruitment that are properly consented for open-access unrestricted use and lymphoblastoid cell line establishment. In Aim 2, we will augment the current pangenome reference by producing high-coverage genomic datasets and assembly workflows necessary to routinely reach finished, T2T genomes. We will do so using a novel combination of sequencing technologies and algorithms that we and others developed to produce the highest quality and most complete genome assemblies to date. We will optimize quality and cost-effectiveness iteratively. All outputs, including protocols, software tools, and quality standards will be made accessible via the NHGRI Genomic Data Science Analysis, Visualization, and Informatics Lab-space (AnVIL) and other resources. In Aim 3, the Genomes Center will engage a team of Ethical, Legal, and Social Implications (ELSI) scholars to identify, address, and develop solutions for key ethical and social issues such as consent, data release, and resource equity. This fully integrated ELSI team will actively participate in decision-making processes, engaging underrepresented groups in pangenome projects. Our Genome Center will be committed to efficient project management and consortium collaboration to ensure the timely completion of all activities. We aim to focus on the generation of a human pangenome reference that optimizes representation of genetic diversity and encourages its use by the genomics research community. To achieve these aims we have assembled an exceptional team consisting of leaders from around the world in consent ethics, sample collection, sample extraction, and high-quality genome sequencing, assembly, finishing, evaluation and annotation. The team also has expertise in using genomic technologies to address a broad range of scientific questions, so is highly cognizant of the practical needs of biomedical researchers who will use this resource. The produced high-quality genomes will be curated and released by our Genomes Center, thereby contributing to the Human Pangenome Reference Resource. Its completion will be essential to the future of precision medicine to ensure that all people, regardless of ancestry, are able to benefit from the promise of genomic medicine.