Current pediatric pressure injury (PI) prevention measures are based on risk factors related to PI development in adults. Children offer a unique concern for PI development because their bodies are still developing, and their skin responds differently to external pressure. To explore risk factors for the development of full-thickness PIs in children aged 21 weeks' gestation to 21 years. This retrospective, observational, correlational study included 799 hospitalized children who developed a PI. The pediatric and adult PI risk factors used in the study were identified from the International Pressure Ulcer Prevention and Treatment Guideline. A stepwise multivariate logistic regression model was used. Multivariate analyses revealed that risk factors for predicting a full-thickness PI varied by age. For children aged 38 weeks to 12 months, risk factors included tissue perfusion and oxygenation: generalized edema, conditions of the OR, and nutrition deficits. For children aged 1 to 7 years, fragile skin status was a risk factor. For youth aged 8 to 21 years, the two risk factors were tissue perfusion and oxygenation: decreased oxygenation and extracorporeal membrane oxygenation. Across the total sample, extracorporeal membrane oxygenation, tissue perfusion and oxygenation: decreased oxygenation and malnutrition were risk factors for predicting a full-thickness PI. Full-thickness PI risk factors differ among the ages of pediatric patients.