B. cereus and B. thuringiensis strains have been associated with gastro-intestinal infections due to enterotoxins production. The possibility of differentiating between B. cereus and B. thuringiensis is a real need in preventing intoxication and in monitoring potentially contaminated foods. The use of DNA comparison provides clearer results than classical microbiological methods in distinguishing B. cereus from B. thuringiensis . The use of a Polymerase Chain Reaction (PCR) followed by Endonuclease Restriction (RE) made the distinction possible in spite of the huge similarity between the two closely related species.