To explore and address these concerns, the Roundtable on Science and Welfare in Laboratory Animal Use hosted a public workshop on October 22-23, 2018, in Washington, DC. The workshop focused on the availability of marmosets in the United States and abroad; animal welfare and ethical considerations stemming from the use of wildtype and genetically modified marmosets; and standards of housing and care, dietary needs, and feeding requirements for marmosets in captivity. This publication summarizes the presentations and discussions from the workshop.