Bdellovibrio and like organisms (BALOs) are a group of predatory bacteria of the delta-proteobacteria class, that prey on some gram negative bacteria. In this study, the biological characteristics of a marine BALOs isolate and its application in the elimination of pathogenic bacteria were investigated. A predator bacterium MMHZ1 was isolated from the coastal waters of the Caspian Sea using a double layer agar technique. Proteus that was isolated from the intestines of a fish was used as prey. The isolate was highly motile and bacteriolytic, and had the ablility to form plaque on the double layer agar medium. The 16S rRNA sequencing analysis revealed that the MMHZ1 isolate was similar to Halobacteriovorax litoralis with 99. 62% homology. Biological characterizations revealed that optimum pH, salt concentration and growth temperature of isolate were 7. 2, 0. 24% and 25 ° C, respectively. The results demonstrated that the isolate was grown only in the presence of live prey, however could not utilize the autoclaved dead bacteria as host. In addition, the study of prey range utilization including some gram negative pathogenic bacteria showed that MMHZ1 lysed 71. 42% of the 14 prey tested. The result of this study demonstrated the applicability of using BALOs to biological control of pathogenic bacteria.