In the present study successful isolation of Aeromonas hydrophila (A. hyd.) was carried out on duck farms and slaughtered shops at Assiut Governorate. 170 samples were examined bacteriologically for determination of the occurrence and frequency of A. hyd.  Diarrhea and emaciation were observed in 50 out of 170 while 20 were apparently healthy at percentage of 30, 15%. Coloacal swabs were obtained from slaughtered ducks in addition to samples from intestinal tract, liver and lung at percentage of 12, 10% and 5%. The result of bacteriological examination revealed that total isolates were 45 at percentage of (26.5%). Inoculation of A. hyd. in chicken embryo through chorio-allantoic membrane (CAM) rout. inoculated embryos die 5 days post-inoculation (P.I.). Died embryos showed sever congestion of internal organs and yolk sac and curling of embryos. Yolk sac, oral and subcutaneous infection in 4 days old duckling revealed deaths of 30, 20% of birds, respectively during observation period in the first and second group but no mortality in the third group. The clinical observation and the post-mortem lesions of experimentally infected birds were recorded. Reisolation of infecting organism from internal organs and intestinal tract of dead and sacrified slaughtered birds at the end of observation period were conducted. The in vitro susceptibility of A. hydrophila isolates to a variety of antibiotics revealed that highest number of isolates were sensitive to Gentamycin Nalidxic acid and Kanamycin while it was resistant to Ampicillin, Penicillin and Colistin-sulphate. The public health significance and the economic losses of A. hydrophila were discussed as well as suggestions for their avoidance.