Objectives: To investigate physical, functional, and psychosocial outcomes in the decades after traumatic brain injury (TBI). Hypothesis: After controlling for gender and severity of injury, both age at injury and years postinjury are predictors of various outcomes after TBI. Participants: A random sample of 243 individuals with TBI, stratified by age at injury and years postinjury, who were injured between 1960 and 2002, and admitted to a single comprehensive rehabilitation facility. Methods: Medical record abstraction and telephone interviews included demographics, injury characteristics, health status, function, alertness, fatigue, depression, postconcussive symptoms, societal participation, environmental barriers, and satisfaction with life. Linear and logistic regression identified effects of age at injury and years postinjury after controlling for gender and injury severity. Results: Increasing years postinjury was associated with declines in physical and cognitive functioning, declines in societal participation, and increases in contractures. Increasing age at injury was associated with declines in functional independence, increases in fatigue, declines in societal participation, and declines in perceived environmental barriers. Conclusions: Both components of aging with TBI (age at injury and years postinjury) influence a variety of physical, functional, and psychosocial outcomes after controlling for gender and severity of injury. This initial investigation suggests that further research on aging with TBI is warranted to better explain and intervene in this phenomenon.