This report explores the feasibility of using electronic health record (EHR) and other electronic health data for research on small populations. The first part of the report illustrates the challenges and limitations of using existing federal surveys and federal claims databases for studying small populations. The second part explores the potential of the increasingly available EHR and other existing electronic health data to complement federal data sources, as well as potential next steps to demonstrate and improve the feasibility of using EHRs for research on small populations.