Variables were studied which predict at the acute stage the functional and occupational long-term outcome for patients with traumatic brain injury (TBI). Glasgow Coma Scale (GCS) score on hospital admission, length of coma (LOC) and duration of post-traumatic amnesia (PTA) were studied in a group of 508 TBI rehabilitation patients, age 0.8-71, mean age 19, followed up between five and over 20 years, mean of 12 years. Information from hospital charts and all data available before and after the injury were gathered and reviewed. The study was carried out among a consecutive sample of Finnish patients with TBI referred to a rehabilitation programme at the out-patient neurological clinic of Kauniala Hospital, which specializes in brain injuries in Finland. The patients came from various hospital districts in the country for an evaluation of their educational and vocational problems. Main outcome measures were functional outcome, as measured by the Glasgow Outcome Scale (GOS) at the end of follow-up, and post-injury occupational outcome. The patients' reemployment on the open job marklet, subsidized employment or inability to work was noted. The GCS score on hospital admission correlated clearly with the functional outcome of the patients at the end of follow-up. Length of coma and duration of post-traumatic amnesia correlated specifically with the patient's work history after the brain injury and with functional outcome measured by the GOS. Outcomes varied among age groups and seemed to be affected by age at injury. Accordingly, the extent of recovery and quality of life for rehabilitation patients with TBI can be estimated early on by prognostic factors reflecting injury severity in the acute phase. The results suggest that the GCS score, LOC and duration of PTA all have a strong predictive value in assessing functional or occupational outcome for TBI patients.