Entomopathogenic Nematodes, This name is indicative of one of the most important methods of modern biological control compared to that the recent discovery of the deadly effect of bacteria which associated the nematode in symbiotic relationship. We believe that the secret in stimulating the early researchers in the field of nematodes came after the beginning of the mode of action of bacteria of Bacillus thuringiensis has been discovered and became comercially using in wide fields. If we look quickly at the history of the discovery of bacteria of Bacillus thuringiensis we will find that Japanese biologist, Shigetane Ishiwatari was investigating the cause of the sotto disease (sudden-collapse disease) that was killing large populations of silkworms when he first isolated the bacterium Bacillus thuringiensis (Bt) as the cause of the disease in 1901. Our goal of this work to refreshment knowledge's about this interest subject by reviewing many studies and activates has been done before and trying to collect it in this condense small book.