Objective To establish reliability and validity of the Pediatric Injury Functional Outcome Scale (PIFOS), a brief injury-specific rating scale covering motor, self-care, communication, social–emotional, cognition, physical, and academic areas. Methods In a prospective longitudinal study, the PIFOS structured interview was administered to parents of children 3–15 years of age at 3 and 12 months after hospitalization for traumatic brain injury (TBI) or orthopedic injury (OI). Results The total score had good internal consistency (α = .90–.93) and inter-rater reliability (α = .90) and correlated significantly with injury severity and neurodevelopmental outcomes. Generalized linear modeling showed the PIFOS was sensitive to the type and severity of injury, showed specific initial and persisting difficulties following TBI and OI, and was responsive to change during the first year after injury. Both groups had residual difficulties with coordination, emotionality, social participation, and discomfort. Conclusion The PIFOS is useful in examining recovery in natural history and intervention studies.