BACKGROUND: Obesity is a known risk factor in adult surgical site infections (SSIs), but its significance in pediatrics is unclear. We hypothesized that overweight and obese children have increased risk for SSI. PATIENTS AND METHODS: A National Surgical Quality Improvement Program-Pediatric (NSQIP-P) file and single-center reviews identified surgical patients (2-18 years) who developed SSIs. Patients were classified as underweight, normal, overweight, or obese based on body mass index (BMI). Comorbidities associated with SSI were analyzed. Sub-specialties and operations were recorded. RESULTS: National Surgical Quality Improvement Program-Pediatric review identified 66,671 patients and 1,380 SSIs. Seven hundred sixty-seven (767) were male and 613 female. Multivariable analysis revealed overweight and obese BMI to be risk factors for SSIs (odds ratio [OR] 1.23, 95% confidence interval [CI] 1.06-1.43; OR 1.43, 95% CI 1.25-1.63). Most commonly, overweight and obese cohorts had superficial incisional SSIs. Pediatric general surgery (3.6%) and cardiothoracic surgery (2.5%) had the highest rates of SSIs. Single-center review identified 115 SSIs. Of these, 29.6% were overweight or obese with few other identifiable SSI risk factors. Sub-specialties with the most SSIs were pediatric surgery and pediatric orthopedics. Appendectomy was the most common procedure associated with SSIs. CONCLUSION: Herein we show elevated BMI to be a significant risk factor for SSIs. This information should be used in assessing and counseling pre-operative pediatric patients and families.