Abstract:61 strains of Bacillus thuringiensis belonging to 31 subspecies, preserved by two methods of sterie sand and filter paper for 1 - 23 years were tested. Their survival,morphological characteristics, toxicity against insects (Lymantria dhaar) were measured. Physiological and biochemical characteristics and estarases of 5 subspecies of Bacillus thuringiensis preserved from 1979 to 1992 were determined.