The effects of a number of hypnotics were compared to a range of results collected for triazolam on objective measures of CNS sedation (critical flicker fusion) and short-term memory function (memory scanning). 2. Assessments taken after the drugs had been administered but prior to the onset of sleep showed that in comparison to placebo most of the compounds were effective sedatives and this correlated highly (r = 0.734, p < 0.04) with amnestic effects found at the same time, suggesting that general CNS sedation is a major component of anterograde amnesia. 3. Residual effects assessed the morning after the hypnotics had been used showed a similar relationship (r = 0.896, p < 0.005). 4. The distribution of results indicates that 0.25 mg triazolam has an acute amnestic profile which is similar to other hypnotics, but possesses a distinct lack of residual effects.