We made a comparative study between the action of barbexaclone and phenobarbital on the electroencephalographic pattern, on the convulsive threshold in rats submitted to continous venous infusion of 4 mg/kg/min of cardiazol (CDZ) and on the motor activity on the mouse. The barbexaclone didn't alter the electroencephalographic pattern of the rat and its anticonvulsive activity was demonstrated by the increase of the convulsive threshold from 66.0 ± 8.3 mg/kg to 111.2 ± 12.75 mg/kg. This increase was similar to that produced by 3.0 mg/kg of phenobarbital. Because the relation between the anticonvulsive doses is of 1:1,4 and in 100 mg of barbexaclone there are only 60 mg of phenylethylbarbituric acid, we conclude that barbexaclone has an equivalent anticonvulsive effect as phenobarbital, with less alterations of the motor activity.