Sixty-nine primary caregivers of adults with a severe traumatic brain injury (TBI) were assessed at 1-year post-injury. Caregivers completed questionnaires on the physical, cognitive, emotional, behavioural, and social functioning of the person with TBI. Caregiver objective burden, psychosocial functioning, and subjective burden were also assessed. Clinically significant levels of anxiety and depression were evident in over a third of the caregivers. Similarly, a quarter of the caregivers reported poor social adjustment. There was no consistent relationship between the prevalence of various types of objective burden and the level of subjective distress that resulted from these changes. The person with TBI's emotional difficulties, in particular their anger, apathy, and dependency, caused the greatest distress for caregivers. With regard to the impact that caregiving had on their own lives, caregivers were most distressed by the loss of personal free time. Results from a regression analysis indicated that the person with TBI's physical impairment, number of behavioural problems, and social isolation were the strongest predictors of caregiver burden. The impact that caring for a person with severe TBI can have on the extended family unit is discussed.