Test materials and naturally infected materials from beehives were used to check the resistance of the European foulbrood causative agents to the disinfection agents vofasteril, performic acid, and iosan and iosan-CCT. It was that Bac. alvei spores are destroyed by 1.5 per cent solution of vofasteril for less than an hour's time and by 1.62 per cent solution of performic acid and 4 per cent iosan--for 4 hours. Bac. paraalvei are still more sensitive: they are destroyed by performic acid and iosan for 1--2 hours.. Sodium dodecylsulfate at the rate of 1 per cent, added to solutions of vofasteril and performic acid, speed up the disinfection action up to four times.