This paper was written not because of the common occurrence of malignant catarrhal fever but because of its close resemblance to the more common diseases IBR and BVD. It is imperative, therefore, that the practitioner keep malignant catarrhal fever in the back of his mind as a differential diagnosis when considering IBR or BVD. If this is brought to the attention of just a few practitioners, the purpose of this paper will be accomplished.