During this study, 20 % mortality was recorded in Dicentrarchus labrax brood stock in marine hatchery of National Institute of Oceanography and Fishery at Alexandria province. Observed clinical signs were decrease appetite, off-food, skin ulcerations and tail erosions. The main post mortem lesion was enlarged liver with presence of hemorrhagic foci. Seven bacterial isolates were recovered by initial isolation on typtic soy agar media from topical lesions (skin, musculature and tail) and from internal organs (heart, liver, spleen and posterior kidney). No growth was detected on specific media including Rimler-Shotts, Pseudomonas selective agar, Thiosulfate Citrate Bile Salts Sucrose agar and Edwards media that indicate absence of major fish pathogens. Identification of the causative agents was performed using VITEK 2 automated biochemical identification system. Four Staphylococcus epidermidis, two Bacillus cereus and one Pseudomonas stutzeri isolates were identified as the causative agents responsible for mortalities in diseased Dicentrarchus labrax. Stress factors induced by hatchery conditions could be the predisposing caused of such infection.