Childhood obesity is a major public health problem in the United States and is associated with numerous comorbidities. The relationship of obesity to risk of traumatic injury and recovery has been described, although not in depth. In adults with burns, obesity has been linked to negative impact on functional outcomes as well as increased mortality. Less is known about the impact of obesity on children with burns. The primary objective of this study was to determine the effect of obesity on length of hospital stay (LOS) among admitted pediatric burn patients. A secondary objective was to compare the difference in burn characteristics between obese and nonobese burn patients. To explore these questions, a retrospective cohort study of patients aged 0 to 18 years admitted to a children's hospital burn unit between February 1, 2000, and September 30, 2006 was performed. For the purposes of this study, obesity was defined as weight-for-length (<2 years of age) or body mass index (> or =2 years of age) > or =95th percentile for age and gender. Patients who had concomitant, nonburn injuries were not included in the study. LOS was measured in days, and an initial univariate analysis examined the association of clinical and demographic factors with LOS. To adjust for confounding, those factors that were found to be significantly associated with LOS were entered into a stepwise linear regression. A total of 528 patients were included in the study group, 17.4% of whom were obese. Obese patients were more likely to suffer a burn of a high-risk anatomic area (72.8% vs 60.8%). Median LOS for obese patients was significantly higher than nonobese (9.3 vs 7.1 days, P < .05). In the adjusted model, factors significantly associated with LOS included total body surface area burned, percent full thickness burn, Medicaid insurance status, and obesity. After controlling for these factors, obese children had a 6.5% longer LOS than nonobese children. This interesting finding raises the question of which factors are responsible for the increased length of stay for obese children hospitalized with burns. Investigating factors such as rate of complications, slower healing, or greater functional impairment may shed light on this finding.