Dutta and Habbu's method was applied to comparative study of cholerogenic properties of the L-strains of cholera vibrios and their initial bacterial variants. In difference from the initial strains, L-forms of cholera vibrios possessed no cholerogenic properties. A possibility of reversion of the stable L-form of cholera vibrios into bacterial form in vivo was revealed. This reversion was accompanied by the restoration of the cholerogenic properties and the change of the biotype of the cholera vibrio.