This study was carried on sheep with clinical signs suggesting pasteurella infection. The sheep belonged to Gahdam farm, Assiut Governorate, Egypt. The disease was manifested in 3 forms acute, subacute and chronic. The acute form of the disease was characterized by septicemia while in the subacute and chronic form the disease showed signs of croupus necrotic pneumonia. Gentamycin treatment was effective in cases suffered from respiratory maifestation, while those suffered from pectoral oedema did not respond to treatment, increased level of globulins associated with decreased level of albumin and albumin globulins ratio in the serum of treated recovered sheep suggested the presence of icnreased antibody production.