3-N,N-Dimethylcarbamoyloxy-7-chloro-5-phenyl-1-methyl-1,3-dihydro-2H-1,4-ben zodiazepin-2-one (Camazepam), a new anxiolytic benzodiazepine with weak muscle relaxant and hypnotic effect, was tested versus diazepam and placebo on reaction time to visual and acustic stimuli with a double-blind cross-over design carried out on 11 healthy volunteer human subjects. The response to acoustic stimuli was more rapid than that to visual stimuli with all the three treatments. The pattern of reaction times after camazepam was similar to that after placebo; diazepam retarded reaction times, with the maximum effect 1 h after the administration. A single dose of camazepam and diazepam considered active on anxiety showed a different effect on reaction times, in that they were not altered by camazepam and were lengthened by diazepam, in comparison with placebo. Data show that 10 mg of camazepam giving an anxiolytic effect do not alter the physical performance.