The present randomized, double-blind, placebo and active-drug controlled, crossover study assessed residual sedation after zaleplon 10 mg, flurazepam 30 mg (as an active control), and placebo, taken during a nocturnal awakening in patients with sleep maintenance insomnia. Twenty-two healthy sleep maintenance insomniacs (11 men; mean age, 42 y) received zaleplon, flurazepam, or placebo after an experimental awakening 3.5 hours after bedtime on two consecutive nights in each of three conditions. Residual sedation was measured with sleep latency testing (5 and 6.5 h postdrug), digit symbol substitution, symbol copying, and subjective sleepiness by visual analog scale, each twice each morning. Zaleplon did not differ from placebo on any measure of residual sedation; flurazepam showed significant sedation on all measures. No residual sedative effects were detected 5 or 6.5 hours after ingestion of zaleplon during the middle of the night by sleep maintenance insomniacs.