About 110 seawater and sediment samples were collected from Alexandria Western Harbor, Egypt, in order to study the antagonistic effect towards different Vibrio sp. (V. fluvialis, V. harveyi and V. damasi). In addition, the occurrence of the Vibrio sp. during five seasons (2012-2013) was also estimated. The results indicated that 31 % of marine isolates inhibited at least one of the tested Vibrio sp. while, 10 % of tested marine isolates showed activity against the tested V. fluvialis, V. harveyi and V. damasi. The highest percentage of antagonistic activity was detected in summer and the Marine sediment samples showed relatively higher antagonistic activity and Vibrio counts compared to the seawater samples. The anti-Vibrio activities were 33 % and 29 %, respectively. While, the occurrences of Vibrio sp. were ranged from 1.92 % to 32.38 % in sediment and from 0.23 % to 13.21 % in seawater samples. The most potent anti-Vibrio isolate was detected as a new marine Bacillus strain with an accession number of KP050555, it identified as Bacillus hwajinpoensis HMA123 using the 16S rRNA gene. The obtained anti-Vibrio activities were 27.50±1.51, 21.36±1.23 and 9.00±0.82 AU against V. fluvialis, V. harveyi and V. damasi, respectively. Also, this new strain showed a broad antibacterial spectrum against Aeromonas sp., Pesudomonas aeruginosa, Streptococcus faecalis and Bacillus subtilis, with activities 23.00±1.53, 15.26±1.18, 8.36±0.93 and 11.16±1.32 AU, respectively. The GC-Mass spectrophotometry of B. hwajinpoensis HMA123 crude extract revealed the existence of fatty acids methyl esters (25.27%), tetracosane (16.06%), hentriacontane (26.65%) and eicosane (32.02%).