The subject of stimulant treatment for patients with neurobehavioural sequelae of traumatic brain injury (TBI) has received a good deal of recent attention, although there have to date been no controlled studies published. This is a description of 15 TBI patients who received treatment with the psychostimulant methylphenidate, in a double-blind, placebo-controlled cross-over study, with behavioural and neuropsychological ratings. Three subjects remained on the drug for a year after the acute study, and were subsequently studied in a double-blind, placebo-controlled reversal. The results support the idea that at least some symptomatic improvement may be gained from low-dose stimulant treatment, although the statistical analysis of the data was compromised by the occurrence of carryover effects from one drug condition to another. This, in itself, is an interesting discovery, because such effects have never been observed in stimulant studies of other patient groups. There are clear implications for the design of further studies in this area. The long-term effects of methylphenidate treatment were not at all impressive, however. Although the findings presented below may be subject to differing interpretation, it is conceivable that stimulants act to advance the course of cortical recovery following TBI.