Summary   The aim of this study was to investigate Enterobacteriaceae infection in freshwater crayfish (red swamp crayfish), Procambarus clarkii, clinical, postmortem findings of examined crayfish, bacteriological examination, rate of infection and organ susceptibility were investigated. 50 freshwater crayfish were subjected to clinical, postmortem and bacteriological examination. Bacteriological examination revealed to isolation of 150 strains from digestive gland, haemolymph, musculature and intestine which are close to morphological and cultural characters to Enterobacteriaceae. Bacteria identification was based on colony morphology and culture behavior on various media, microscopic examination, biochemical tests and carbohydrate fermentation. 150 strains were identified as Edweardsiella tarda (16), Proteus vulgaris (10), Proteus mirabilis (62), Salmonella (32) and 30 isolates were not identified. Bacteriological examination revealed the best organ for isolation of E. tarda is intestine, while musculature is the best site for isolation of Proteus vulgaris, and Salmonella. Moreover, hepatopancrease is the best organ for isolation of Proteus mirabillis.