A total of 200 freshwater Crayfish were collected separately during late summer 2011 and 2012 from different natural water resources of River Nile, Dakahlia governorate. Diseased crayfish showed focal heamorrahges on cuticle, liquifacation of hepatopancreas and/or congestion. Clinical findings and postmortem lesions of naturally infected crayfish were lethargy and erosions associated with softening and darkening of hepatopancreas. The detected isolates were Aeromonas hydrophila which were of higher prevalence (35%),Pseudomonas aeruginosa in a rate of 3%, Escherichia coli in a rate of 5% and Proteus spp in a rate of 5%. Molecular identification revealed that A. hydrophila harbor the lip gene at 760bp. Histopathological findings were varied from severe to mild degenerative changes among infected tissues.