SUMMARY Septicemic disease occurred in 49 of 126 pigs several days after being transported 80 km. All affected pigs died. The main changes in acutely affected pigs were skin discoloration, pulmonary edema, arthritis, meningitis, and renal glomerular thrombosis. In peracute cases, gross findings were minimal. Haemophilus parasuis was isolated from multiple organ sites in most affected pigs. Haemophilus parasuis was isolated from nasal swab specimens from 17 of 20 clinically normal pigs on the farm of origin. Fatal acute septicemia was reproduced in 2 pigs by intravenous or intratracheal exposure to an isolant of H parasuis obtained from 1 of the 49 fatally affected pigs. Aerosol exposure of 5 pigs resulted in mild pneumonia in 4 pigs and severe pneumonia, pleurisy, pericarditis, and terminal septicemia in 1 pig.