The present study was conducted to investigate isolation and antimicrobial drug susceptibility of Pasteurella spp from pneumonic calves and cows (pneumonic lungs) in Gyeongnam south area from January to November 2000. Pasteurella multocida and P haemolytica were isolated 136 (53.8%) and 22(8.7%), respectively, from 158 of 253 pneumonic calves of 1 to 12 months of age and from pneumonic lungs and simultaneous isolation rate of P mutocida and P haemolytica was 4 (1.6%). Seasonal isolation rate of Pasteurella spp in calves and pneumonic lungs varied from 3 to 65.2%, and it was higher in Fall. The majority of biochemical and cultural properties of P multocida and P haemolytica isolated from calves and pneumonic lung were identical to those of the reference strains employed. Pneumonic lesions of the examined lungs were histologically identified as purulent bronchopneumonia and fibrinous pneumonia. All isolates were resistant to penicillin, amikacin, lincomicin, colistin, cloxacilling, sulfonamide, kanamycin, sulfamethoxasoletrimetoprim, and gentamicin(>80%), but some of them were susceptible to amoxicillin, norfloxacin, cephalexin, cefazolin, orbifloxacin, enrofloxacin, and ciprofloxacin(>60%).