The DNA probe SW15 derived from the laboratory-attenuated Alcelaphine Herpesvirus-1 (AHV-1) strain WC11 as well as from the polymerase chain-reaction test (Hsu, Shih, Castro & Zee 1990), was used to detect viral DNA of malignant catarrhal fever (MCF) in six experimentally infected cattle. Heparinized blood samples were collected and tested at least three times a week over a period of up to 142 d. Results of hybridization and PCR tests were compared with the results of clinical examinations, and on various occasions with those of viral isolation and serum-neutralization assays as well as with those of pathology. Three animals developed clinical signs and lesions typical of MCF, while the other three animals remained clinically healthy. All cattle seroconverted, and viral nucleic acid was detected by DNA hybridization and PCR at various intervals during the observation period. Virus isolation was successful in two of the clinical cases and all cattle seroconverted. Storage of blood samples at 4°C for up to 10 d did not influence the hybridization and DNA-amplification results.