The characteristics of lung lesions of slaughtered lambs and the presence of microorganisms in the lesions were investigated. Pneumonia was detected in 500 (3.6%) of 13,588 lambs. Macroscopical lesions were of atypical pneumonia and were often seen in the pars cranialis of lobus cranialis dexter. Histologically, proliferative pneumonia was detected in most cases and was often accompanied by exudative characteristics. Pasteurella haemolytica was isolated from 258 (51.6%) and Mycoplasma ovipneumoniae from 215 (43.0%) of 500 pneumonic lungs. In 131 (26.2%) cases both organisms were isolated from same samples. A close relationship was found between P. haemolytica and exudative inflammation (p < 0.05).