This paper briefly reviews sleep laboratory studies on the treatment efficacy of methylphenidate, pemoline, dextroamphetamine and methamphetamine. The literature indicates that 1) methylphenidate, dextroamphetamine, pemoline and methamphetamine objectively improve somnolence as measured by the Multiple Sleep Latency or Maintenance of Wakefulness Tests (MSLT or MWT); 2) pemoline, at doses up to 112.5 mg, is less effective in controlling somnolence than methylphenidate, dextroamphetamine and methamphetamine; 3) there are dose-dependent improvements in performance that parallel MSLT and MWT data; and 4) at the highest doses of stimulants studied to date, narcoleptics, although improved, still did not function on MSLT or MWT and most performance tests at levels comparable to those of control subjects. Future research designs should address issues of placebo effect, practice effects and the degree to which alertness and performance measures can be pharmacologically brought up to levels comparable to those of normal control subjects.