||The goal of the workshop “Planning a Virtual Down Syndrome Cohort Across the Lifespan” is to develop a plan to meet the goals of INCLUDE Component 2, namely, development of a cohort to perform deep phenotyping and study co-existing conditions to develop a comprehensive genomic, epigenomic, transcriptomic, and proteomic map to help understand the predisposing risk and protective factors that underlie the highly penetrant features in Down syndrome. The INCLUDE (INvestigation of Co-occurring conditions across the Lifespan to Understand Down syndromE) project was launched in June 2018. We plan to convene an NIH-supported Workshop with experts in Down syndrome research, data science, data privacy, cohort development, research, applicable clinical specialties, mHealth, as well as individuals with Down syndrome and their families, and advocacy organizations to plan not only the practical aspects of aggregating existing DS cohorts, but also the best approaches to expand the cohorts prospectively, the most pressing scientific questions to be answered initially, and the resources that will be needed. The workshop is conceived in two components: the first is focusing on the clinical aspects of Down syndrome and the ‘omics and biospecimens needs of the program; the second is focused on the data harmonization, sharing, and IT needs of the program. At the end of the workshop, we hope to have a blueprint for creation of a DS cohort across the lifespan.