Context The rates of appendiceal rupture and negative appendectomy in children remain high despite efforts to reduce them. Both outcomes are used as measures of hospital quality. Little is known about the factors that influence these rates. Objective To investigate the association between hospital- and patient-level characteristics and the rates of appendiceal rupture and negative appendectomy in children. Design, Setting, and Patients Retrospective review using the Pediatric Health Information System database containing information on 24 411 appendectomies performed on children aged 5 to 17 years at 36 pediatric hospitals in the United States between 1997 and 2002. Main Outcome Measures Rates of negative appendectomy and appendiceal rupture; the odds ratio (OR) of negative appendectomy and appendiceal rupture by hospital, patient age, race, and health insurance status, and hospital fiscal year and appendectomy volume. Negative appendectomy rate was defined as the number of patients with appendectomy but without appendicitis divided by the total number of appendectomies. Results The median negative appendectomy rate was 3.06% (range, 1%-12%) and the median appendiceal rupture rate was 35.08% (range, 22%-62%). The adjusted OR for appendiceal rupture was higher in Asian children (1.66; 95% confidence interval [CI], 1.24-2.23) and black children (1.13; 95% CI, 1.01-1.30) compared with white children. Children without health insurance and children with public insurance had increased odds of appendiceal rupture compared with children who had private health insurance (adjusted OR, 1.36; 95% CI, 1.22-1.53 for self-insured; adjusted OR, 1.48; 95% CI, 1.34-1.64 for public insurance). No correlation existed between negative appendectomy rate and race, health insurance status, or hospital appendiceal rupture rate. The negative appendectomy rate improved as the hospital appendectomy volume increased. Conclusion The rate of appendiceal rupture in school-aged children was associated with race and health insurance status and not with negative appendectomy rate and therefore is more likely to be associated with prehospitalization factors such as access to care, quality of care, and patient or physician education.