It is estimated that up to one-third of persons with known human immunodeficiency virus (HIV) infection in the United States are not engaged in care. We evaluated factors associated with patients' failure to establish outpatient HIV care at our clinic and found that females, racial minorities, and patients lacking private health insurance were more likely to be "no shows." At the clinic level, longer waiting time from the call to schedule a new patient visit to the appointment date was associated with failure to establish care. Because increased numbers of patients will be in need of outpatient HIV care as a result of recent Centers for Disease Control and Prevention guidelines advocating routine HIV testing, it is imperative that strategies to improve access are developed to overcome the "no show" phenomenon. © 2007 by the Infectious Diseases Society of America. All rights reserved.