Objectives: To identify factors relating to the intensity of rehabilitation services received and to ascertain the relation between injury outcomes, demographics, types of therapy, and the intensity of rehabilitation services provided. Design: A multicenter, prospective, nonrandomized study with inpatient rehabilitation data collected between 1989 and 1996. Setting: Three medical centers in the federally sponsored Traumatic Brain Injury Model Systems. In each setting, the continuum of care includes emergency medical services, intensive and acute medical care, and inpatient rehabilitation. Participants: A total of 491 consecutively enrolled patients with a mean age ± standard deviation of 34.3±15.88 years recruited from 3 medical centers. To be included in the study, patients must have been at least 16 years of age, have presented to the emergency department within 24 hours of injury, and have received acute care and inpatient rehabilitation. Interventions: Patients received comprehensive medical care along with a combination of rehabilitative therapies, including physical, occupational, psychologic, and speech therapy. Main Outcome Measures: Therapy intensity; levels of functional independence, cognitive function, functional gain, and treatment efficiency, as indicated by the FIMTM instrument; rehabilitation length of stay (LOS); and charges. Results: Age predicted the intensity of both psychologic (P<.001) and total therapy (P<.01) services. Acute care LOS was also a significant predictor of psychologic services (P<.01). Only admission motor FIM was relevant in predicting speech services intensity (P<.01). Therapy intensity was predictive of motor functioning at discharge (P<.001). However, therapy intensity did not predict cognitive gain (P<.05). Conclusions: This study is among the first multicenter efforts to examine the potential benefits of individual therapy services. Findings support assertions that increased therapy intensity, particularly physical and psychologic therapies, enhances functional outcomes. © 2003 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.