Immunohistochemical investigations were carried out to determine organ and cellular localization of the rabbit haemorrhagic disease viral antigen (RHDVA). It was found in certain parenchymal liver cells near the interlobular septs and in some macrophages and pseudoeosinophils of all studied organs and blood. Whereas in morphologically preserved hepatocytes and macrophages the RHDVA accumulated in the nuclei, in cells with disintegrated nuclei it was distributed throughout the cytoplasm.