This study examined sustained attention abilities 24 months postinjury, in 3 groups of children who had suffered a traumatic brain injury (TBI): (a). mild TBI (n = 24), (b). moderate TBI (n = 31), and (c). severe TBI (n = 14). Three manipulations of the traditional Continuous Performance Test paradigm (CPT) were employed in the study, to delineate factors that might influence CPT performance, including speed of processing, attentional lapses, and stimulus complexity. No significant differences were evident among the TBI groups on a measure of simple reaction time, nor on a CPT version where the interstimulus interval was lengthened. However, there was a significant difference between the mild and severe TBI groups on the most complex task, which required speed, accuracy, and decision making, suggesting that these factors underlie impaired performances previously identified on the CPT in children with severe TBI. These findings have implications for the development of intervention programs for these children.