Nasopharyngeal swabs were collected from 100 lambs aging 9 -12 months (30 healthy and 70 pneumonic lambs for bacteriological examination. Overall, 25% were positive for P multocida. Antibiogram study of the isolates revealed that marbofloxacin was the highest effective against P. multocida. Forty lambs (20 healthy and 20 naturally infected with P multocida) were divided into 8 groups (5, each), the 1st group: healthy lambs (control), 2nd group: healthy received marbofloxacin, 3rd group: healthy received flunixin meglumine, 4th group: healthy received marbofloxacin and flunixin meglumine together, 5th group: infected non treated, 6th group: infected treated with marbofloxacin, 7th group: infected treated with flunixin meglumine and 8th: group infected treated with marbofloxacin and flunixin meglumine together. Hemato-biochemical changes at 1st, 7th and 14th day post treatment were studied. All clinical sign disappeared and P.multocida microorganisms were not reisolated in group post treated by marbofloxacin alone or together with flunixin meglumine. Healthy lambs received marbofloxacin or flunixin meglumine either alone or together showed significant decrease in RBCs, Hb, PCV%, T protein, albumin, globulin, α, β, γ globulin and significant increase in WBCs, AST, ALT, ALP, GGT, urea and creatinine at1st and 7th day post injection. Pneumonic lambs showed significant reduction in RBCs, Hb, PCV% T. protein, albumin, total globulin, α, β globulin and significant increase in WBCs, AST, ALT, ALP, GGT, γ globulin, urea and creatinine all over the experimental period. Pneumonic lamb treated with marbofloxacin alone or with flunixin meglumine resulted in complete disappearance of these clinical signs at 1st day post treatment but these clinical signs remained in flunixin meglumine alone lambs. It is concluded that, pasteurellosis in lambs resulted in adverse effect in hematobiochemical parameters. Using marbofloxacin alone or together with flunixin meglumine in treatment of diseased lambs lead to improve clinical signs and hemato-biochemical parameters at 7th day post treatment.