An outbreak of acute bovine pulmonary oedema and emphysema (ABPE), which occurred in the south central Chile at the end of the summer of 1995, is described. The Friesian cattle, approximately 2 years old, which were affected presented severe signs of expiratory dyspnoea after they were moved from a fibrous pasture to one which was lush with alfalfa. Mortality rate was 23%. The main lesions found in the necropsy were severe interstitial emphysema and oedema of the lungs. These were corroborated by histopathological findings in the lungs which showed an hyperplasia of type II pneumocytes as well as the presence of hyaline membranes. Syntomatic treatment was given at the outset of the diseases. But did not have any positive results