A large outbreak of the peracute form of malignant catarrhal fever in cattle in Belgium is described.The main symptoms were nervous signs and high fever. Over a four-month period, 13 BelgianBlue yearlings and one cow died. Mortality was 16.3% of the herd. The diagnosis was confirmedby identifying ovine herpesvirus-2 DNA by PCR, both in the affected cattle and in the sheep on thefarm. This case report illustrates the increasing importance of malignant catarrhal fever as a herdproblem and the occurrence of the peracute form, as also reported in other European countries. Italso illustrates the importance of malignant catarrhal fever as a differential diagnosis for nervousdisorders in cattle.