This paper reports on several aspects of the taxonomy and biology of the symbiotic bacteria, Xenorhabdus spp. and Photorhabdus luminenscens, associated with entomopathogenic nematodes (EPNs), Steinernema spp. and Hetereorhabditis indica, and commonly has a function as a biological control of insect pests. The bacterium complexes was isolated from four entomopathogenic nematodes local isolates and characteristized by physiology, morphology, and distribution. Based on the morphological and physiological tests, these four local isolates of bacteria symbiont of entomopathogenic nematodes from Jember, Bondowoso, Probolinggo, and Malang were determined as Xenorhabdus spp. and from Ngadas and Probolinggo were Photorhabdus luminenscens. This bacteria was tolerance at 18 – 37 oC and pH 5 – 7. It is considered that Xenorhabdus spp. – Steinernema spp. and Photorhabdus luminenscens – Heterorhabditis indica were broadly distribute in East Java.