In this retrospective study we report our 12 years' experience of the Wada test (intra-carotid injection of short half-life barbiturates) using Methohexital. The clinical manifestations induced by Methohexital were similar to those observed with Amobarbital. The inocuity of the test is attested by the finding that no incident or accident has been reported in 126 injections, the risk being the same as for arteriography. The two main advantages of Methohexital over Amobarbital are: 1) short hemispheric narcosis, which makes it possible to explore the two carotid arteries territories during the same session and limits the risk of drug diffusion to the two hemispheres; 2) the rare occurrence of vigilance troubles such as drowsiness or falling-asleep, which are frequently observed during Amytal Wada test. Intracarotid Methohexital injections are effective to determine the hemispheric lateralization of language and useful to evaluate the role of each hemisphere in memory, especially before the surgical treatment of drug-resistant focal epilepsies.