Background: Advances in emergency medicine, both in the field and in trauma centers, have dramatically increased survival rates of persons sustaining traumatic brain injury (TBI). However, these advances have come with the realization that many survivors are living with significant residual deficits in multiple areas of functioning, which make the resumption of a quality lifestyle extremely difficult. To this point, TBI has recently been characterized as a chronic disease. As with other chronic diseases, TBI is often causative of persistent disabling symptoms in multiple organ systems. Therefore, posthospital residential rehabilitation programs have emerged to treat these symptoms with the goal of helping these individuals regain function and live more productive and independent lives. Purpose: This study examined the nature and severity of residual deficits experienced by a group of 285 brain-injured individuals and evaluate the efficacy of posthospital residential rehabilitation programs in treating those deficits. Method: Participants consisted of 285 individuals who had sustained a TBI and, due to multiple residual deficits, were unable to care for themselves, necessitating admission to residential posthospital rehabilitation programs. All participants were evaluated at admission and discharge on the Mayo-Portland Adaptability Inventory-Version 4 (MPAI-4). The MPAI-4, developed specifically for persons with acquired brain injury, measures 29 areas of function often affected by TBI. Results: From the 29 skills evaluated, the 12 most often rated as causing the greatest interference with function were identified. Of these skills, the cognitive deficits including memory, attention/concentration, novel problem solving, and awareness of deficits were highly correlated with disruption in performing everyday societal roles. The impact of treatment for reducing the level of disability in these areas was statistically significant, t(284) = 17.43, p < .0001. Improvement was significant even for participants admitted more than 1 year postinjury, t(78) = 8.05, p < .0001. Conclusions: Skill deficits interfering with reintegration into home and community are highly interrelated and should be treated with the understanding that progress in one area may be dependent on change in another area. Cognitive skills including memory, attention/ concentration, novel problem solving, and awareness of deficits were highly correlated with measures of overall functional outcome. Posthospital programs using a multidisciplinary treatment approach achieved significant reduction in disability from program admission to discharge. The benefits of these programs were realized even for the most chronically-impaired participants.