An infectaous outbreak involving Haemophilus pleuropneumoniae affecting a 2000 pigherd farm in the Metropolitan Region is reported for the first time in Chile. A morbidity of 10% and 15% was observed in post weaning and growing finishing pigs, respectively. The mortality rates for post weaning, growing and finishing pigs were 2.6%, 0.5% and 1.1% respectively. The lesions were restricted to the thoracic cavíty and they consis­ted of delimited pneumonic focuses, fibrinous pleuritis and a great amount of serous bloody liquid. Hemorrhagic infarcts were seen microscopically. Bacteriological isolation from pneumonic lesions and mediastinic lymph nodes demonstrated the presence of a pure culture, which according to its biochemical and growing characteristics it correspon­ded to Haemophilus pleuropneumoniae. Se describe un brote infeccioso en un plan­tel industrial de 2.000 cerdos de la Región Metro­politana que alcanzó una morbilidad de 10% y 15% en recría y crianza-engorda y, una mortali­dad de 2,6% 0,5% y 1,1% en recría, crianza y engorda, respectivamente. Las lesiones, restrin­gidas a la cavidad torácica fueron focos neumóni­cos delimitados, pleuritis fibrinosa y gran canti­dad de líquido serosanguinolento; microscópi­camente las lesiones neumónicas correspondie­ron a infartos hemorrágicos. Desde lesiones neumónicas y ganglio medias­tínico se aisló puro un bacilo pleomórfico Gram negativo, cuyas colonias mostraron satelitismo al­rededor de S. aureus y de factor V suministrado en disco, clara zona de hemólisis y reacción CAMP positiva sobre agar sangre ovina con es­tría de S. aureus, lo que junto a otras caracterís­ticas permitieron identificarlo como Haemo­philus pleuropneumoniae.