We report a patient with chronic lung abscess due to Pasteurella multocida infection that may be caused by the contact with cows in his workplace. Despite its apparent rarity, chronic abscess due to P. multocida should be considered in the differential diagnosis of solitary pulmonary masses. This case report suggests that P. multocida infection can be potentially caused from saliva of cows as well as dogs or cats. (Internal Medicine 44: 754-756, 2005)