The neuropsychological functioning of a group of 65 adults with severe traumatic brain injury was assessed at 6 months and 1 year post-injury. The cognitive domains assessed were pre-morbid intellectual level, current level of general intellectual functioning, simple and complex attention, verbal memory, executive functioning, and perceptual functioning. At least 40%, and up to 74%, of the TBI patients displayed some degree of impairment on tests administered at 6 months. Improvement was found to occur in all areas of cognitive functioning over the first year following injury. Despite this improvement at least 31%, and up to 63%, of TBI patients displayed some degree of impairment on tests administered at 1 year post-injury. The various types of neuropsychological functioning were affected to different degrees, indicating that different aspects of cognition are more susceptible to injury, and that recovery takes place at a differential rate across functions. The implications of these findings for the appropriate planning and allocation of treatment and rehabilitation resources, and the development of effective rehabilitation interventions are outlined.