Pneumonic pasteurellosis in cattle is a disease complex caused by the interaction between bacterial and viral infectious agents, environmental conditions and management practices. Pasteurella haemolytica is the primary bacterial agent usually associated with mortality although P. multocida can be involved to a lesser degree. No single management practice will be effective in controlling this disease complex. The key to control is an integrated approach beginning on the ranch with vaccination and exposure to feedlot conditions followed by subsequent revaccination at entry into the feedlot. Prophylactic mass medication in the feedlot has been shown to be the most effective method for reducing losses due to Pasteurella infection. Management practices which reduce stress, as well as early diagnosis and antibiotic treatment, are the key methods of controlling disease within the feedlot, especially during the first two to three weeks after arrival.