An influenza pandemic would have a disproportionately adverse impact on minority populations, the poor, the uninsured, and those living in underserved communities. Primary care practices serving the underserved would face special challenges in an influenza pandemic. Although not a formalized system, components of the primary care safety net include federally qualified health centers, public hospital clinics, volunteer or free clinics, and some local public health units. In the event of an influenza pandemic, the primary care safety net is needed to treat vulnerable populations and to provide health care surge capacity to prevent the overwhelming of hospital emergency departments. We examined the strength, capacity, and preparedness of key components of the primary care safety net in responding to pandemic influenza.