Restriction endonucleases have been isolated from 26 strains of thermophilic strains of the Bacillus genus, their recognition sequences were determined, and for 15 of them cleavage sites identified. The enzymes proved to be isoschizomers of known endonucleases BstNI, EarI, HaeIII, HpaII, Cfr10I, BsiYI, BclI, BbvII, BbvI, BstEII, BsaBI, BsrI, FspI, ClaI, SfeI.