Emergency rooms are used frequently by patients who do not require urgent treatment. Furthermore, a small but sizable number of these patients in busy emergency rooms leave (walk out) before they are actually examined by medical personnel. Data were analyzed for all patients presenting to a university-affiliated hospital emergency room during a one-year period. Six hundred forty-four persons left the emergency room before being seen (leavers). Based on a code routinely assigned to their presenting complaint, patients were divided into urgent and nonurgent categories. A random sample of 100 leavers was matched with nonurgent stayers by age, sex, race, and shift of presentation. Information was collected from medical records and telephone interviews. A multiple discriminant analysis revealed the following profile of the leaver: a person who lives within 21/2 miles of the hospital has either Medicare/caid or no medical insurance, has no private physician, and has a nonserious presenting complaint. Stayers, on the other hand, have more serious complaints, tend to have medical insurance, more often have a private physician, and may live at any distance from the hospital. In addition, leavers presented with drug, alcohol, or psychiatric problems more frequently than stayers. Leavers, on the average, spend 90 minutes waiting for treatment they never receive. This study characterizes a small but problematic subgroup for emergency department planners and suggests the need for community-based health education and referral of such patients to primary care centers.