The performance- and alertness-sustaining/restoring effects of modafinil during sleep deprivation in normal, healthy adults were reviewed. Results indicate that modafinil is efficacious for sustaining/restoring objective performance and alertness during sleep deprivation with few adverse effects. At appropriate dosages, modafinil restores performance and alertness to non-sleep deprived levels. Modafinil also impairs post-sleep deprivation recovery sleep, but from the few studies available addressing this issue, it is unclear whether these sleep impairments translate into post-sleep performance impairments. Further research is needed to determine whether modafinil restores performance on simple cognitive tasks only or whether modafinil additionally restores executive functions (e.g., abstract thought, critical reasoning, planning, decision-making, situational awareness, and effective judgment) which are critical in most modern operational settings. In addition, studies are needed to determine whether modafinil use during sleep deprivation is preferable to that of other available controlled stimulants (such as dextroamphetamine) or non-controlled stimulants (such as caffeine). Such studies would be comprised of direct, head-to-head comparisons among various stimulants across a range of dosages.