We describe a population of 296 patients (1.1% of 27,230 pediatric emergency department visits) who left a pediatric ED without treatment during a 12-month period. Most occurred on weekends (n = 120; 41%), registered between 4 PM and midnight (n = 174; 59%), were on public aid (n = 161; 54%), had no known source of health care (n = 188; 64%), and waited less than three hours before leaving (n = 187; 63%). Most were not seriously ill; 12 children (4%) had urgent or emergency problems. Minor trauma was the most common reason for the visit. Two hundred twenty-three (75%) were contacted by telephone two days later. A long waiting time was the most commonly cited reason for leaving (137/231; 59%). One hundred sixteen patients (52%) did not seek other medical care; 36 (16%) went to another hospital ED. Forty-eight hours after leaving without treatment, 112 patients (50%) were well, 65 (29%) had improved, 34 (15%) were unchanged, two (less than 1%) were worse, and seven (3%) had been hospitalized.