Background: Acute kidney injury (AKI) significantly increases morbidity and mortality for hospitalized children, yet sociodemographic risk factors for pediatric AKI are poorly described. We examined sociodemographic differences in pediatric AKI amongst a national cohort of hospitalized children. Methods: Secondary analysis of the most recent (2012) Kids’ Inpatient Database (KID) from the Agency for Healthcare Research and Quality. Study sample weights were used to obtain national estimates of AKI (defined by administrative data). KID is a nationally representative sample of pediatric discharges throughout the USA. Linear risk regression models were used to assess the relationship between our primary exposures (race/ethnicity, health insurance, household urbanization, gender, and age) and the diagnosis of AKI, adjusting for comorbidities. Results: A total of 1,699,841 hospitalizations met our study criteria. In 2012, AKI occurred in approximately 12.3/1000 pediatric hospitalizations, which translates to almost 30,000 children nationally. Asian/Pacific Islander, African-American, and Hispanic children were at slightly increased risk for AKI compared to Caucasian children (adjusted risk difference (RD) 4.5 per 1000 hospitalizations, 95% confidence interval (CI) 2.9–6.0; 2.5/1000 hospitalizations, 95% CI 1.7–3.3; and 1.7/1000 hospitalizations, 95% CI 0.9–2.5, respectively). Uninsured children were more likely to suffer AKI compared to children with any health insurance (e.g., no insurance versus Medicaid_ adjusted RD 14.4/1000 hospitalizations, 95% CI 12.7–16.2). Based on these national estimates, one episode of AKI might be prevented if 70 (95% CI 62–79) hospitalized children without insurance were provided with Medicaid. Conclusions: Pediatric AKI occurs more frequently in racial minority and uninsured children, factors linked to lower socioeconomic status.