Free Clinics (FCs) in the United States contribute to the healthcare safety net by providing care to a variety of populations including the uninsured. Data Envelopment Analysis (DEA) is used to evaluate FC performance by examining clinic funding sources and the number of visits and prescriptions provided on an annual basis. Cross-sectional data including 48 Virginia FCs in 2010 are analyzed to distinguish efficient and inefficient FCs. In all, 30 clinics (62.5%) were found to be top performers and defined the efficiency frontier, whereas 18 clinics (37.5%) were evaluated as inefficient. On average, to obtain efficiency, inefficient clinics would annually need to increase the number of provided general medical visits by 2,183, specialty visits by 1,969, other visits by 1,495, and dispensed prescriptions by 7,305. These findings have implications for healthcare policy and FC management.