210 shell diseased shrimps (Penaeus japonicas) were collected and taken alive from port-said governorate. Shell diseased shrimps were taken monthly from January to October 2016 and subjected to clinical, postmortem, bacteriological and histopathological examinations. In addition of 15 apparently healthy shrimps, free from any shell lesions were collected and taken alive from port-said Governorate were used in the experimental infection (pathogenicity test). Results revealed that the isolated bacteria from shell diseased shrimps were identified as Vibrio alginolyticus and Vibrio parahemolyticus. The number of isolates for Vibrio alginolyticus was 568 isolates by incidence of 77.59%, Vibrio parahemolyticus was 131 isolates by incidence of 17.89%, It was found that Vibrio alginolyticus, Vibrio parahaemolyticus, were highly isolated from the muscles by ratio of 95.71%, the cuticle by ratio of 90% then from gills by ratio of 80% followed by the hemolymph by ratio of 51.90%, while it was less isolated from the hepatopancrease by ratio of 30.95%.The pathogenicity test of the isolated microorganisms showed nearly the same clinical picture and postmortem findings which observed in naturally infected shrimps and isolated  vibrio speciesappear to be highly virulent gave 100% mortality in 60 hrs. of the experimental infected shrimps. Vibrio alginolyticus and Vibrio parahemolyticus were sensitive to Norofloxacin, Ciprofloxacin and Trimethoprim-Sulfamethoxazole and resistant to Amikacin and Rifamycin. The histopathological studies among naturally infected shrimps (penaeus japonicas) revealed changes in muscles, gills and hepatopancrease due to infection as intermuscular edema, inflammatory cells between muscle bundles and degeneration and necrosis of muscles, the gills showed squamous metaplasia, and the hepatopancreas showed congestion in the hepatic vessels, advanced vacuolar degeneration with nuclear pyknosis of most hepatocytes were evident.