A total of 51 samples (43 nasopharyngeal swabs and 8 lung tissues) were taken from 43 animals of private sheep flock at Dakahlia province some of which were showing respiratory manifestations, the examined include 30 lambs (8 emergency slaughtered, 14diseased and 8 apparently healthy) and 13 adult sheep (9 diseased and 4 apparently healthy). The bacteriological examinations revealed that 58.14% of examined animals were positive for pasteurella species, Mannheimia hemolytica (M.hemolytica) represent the most common isolates as 41.86% while 23.26% were infected with pasteurella multocida (P.multocida) . Mixed infection with the isolated species was found as 6.98%. Meanwhile the isolated species were pathogenic for mice. On the other hand, the sensitivity test in vitro for pasteurella specis proved that all examined isolates were sensitive for norfloxacine and enrofloxacine while 94.12% and 88.24% were sensitive for oxytetracycline and ciprofloxacine respectively, on the other hand all isolates were resistant for amoxacillin and gentamycin but 76.47% of the isolates were resistant for streptomycin and lincomycin.