The College of Science at the University of Basrah organized a seminar entitled (Biodiversity of killer toxins and the ecological significance of their production) by Khalid Nasser Diwan . The study aims Study of the killer toxins produced by killer yeasts and knowledge of the killing mechanism of these toxins and what is the mechanism of action of these toxins and their practical applications. The study included the types of killer toxins and their effect on some yeasts and other microorganisms and knowledge of their genetic determinants and the biological diversity of these toxins and methods of analyzing the measurement of the killer activity of these toxins.