Traumatic pericarditis was confirmed postmortem in 28 cattle that had shown signs of a heart rate of more than 100 bpm, distended jugular veins and muffled heart sounds or abnormal pericardial sounds. The heart rate was higher than normal in 24 of them, and in 18 of these it ranged from 100 to 130 bpm. Twenty of the cattle had muffled heart sounds and 10 had pericardial sounds, such as splashing, rubbing or squeaking sounds. Both jugular veins were distended in 24 of the cattle, and 15 had oedema of the throat region, brisket and ventral abdomen. The most important laboratory findings were a reduced clotting time in the glutaraldehyde test in 26 animals, leucocytosis in 22 and a higher than normal concentration of fibrinogen in 19. There was an increase in the activity of gamma-glutamyl transferase in 20, and of aspartate aminotransferase in 15, and in the concentration of bilirubin in 11 of the cattle, indicative of hepatic congestion. A definitive diagnosis of traumatic pericarditis was made on the basis of the clinical findings in 15 of the 28 animals, all of which had typical signs of the disease. In another eight animals, traumatic pericarditis was suspected, although one of the characteristic signs was absent. A tentative but incorrect diagnosis of valvular endocarditis was made in three animals, and a similarly incorrect diagnosis of traumatic reticuloperitonitis was made in the other two.