Based on a retrospective 5-year medical record review, this study characterizes factors associated with patients discharged against medical advice (AMA) from a tertiary pediatric emergency department (ED) and compares rates of return to the ED and admission to the hospital with those of patients routinely discharged. Data from 94 patients discharged AMA are compared with those of 188 control patients. Pediatric patients at risk for discharge AMA are older than 15 years (odds ratio [OR], 3.561; 95% confidence interval [CI], 1.695-7.482), self-register independent of a parent (OR, 3.100; 95% CI, 1.818-152.770), arrive by ambulance (OR, 2.761; 95% CI, 1.267-6.018), involve a consultant (OR, 2.592; 95% CI, 1.507-4.458), and have a chief complaint of abdominal pain (OR, 3.095; 95% CI, 1.154-8.303). Negative predictors include urgent triage (OR, 0.155; 95% CI, 0.039-0.618), a chief complaint of upper respiratory tract illness or otitis media (OR, 0.229; 95% CI, 0.075-0.702), and discharge diagnoses of infection (adjusted OR, 0.053; 95% CI, 0.004-0.767), disease of the nervous system and sense organs (adjusted OR, 0.066; 95% CI, 0.005-0.898), respiratory illness (adjusted OR, 0.072; 95% CI, 0.007-0.718), and gastrointestinal disease (adjusted OR, 0.050; 95% CI, 0.006-0.419). Certain key elements of discharge AMA are well documented, including consequences of discharge AMA (74.5%) and instructions for care (54.3%). Other elements such as alternative therapies (1.1%) are poorly documented. Patients discharged AMA have a significantly higher return rate (24.5%) within 15 days compared with patients who have routine discharge (6.4%) (chi2=18.85, P<.001). Ninety-six percent of patients who return to the ED have the same chief complaint at both visits if discharged AMA compared with 50% of patients who are discharged routinely (P=.003), with 25% admission rates at the time of second visit for both types of discharges. Adolescents who register themselves are at increased risk for discharge AMA. Patients who are triaged as urgent or nonurgent or who have minor illnesses are likely to be dispositioned routinely. Patients discharged AMA are more likely to return to the ED with the same complaint than patients who are routinely discharged.