The causative agent of rabbit viral haemorrhagic disease (VHD) was purified by CsCl density gradient centrifugation from liver homogenates of rabbits infected with a strain of VHD virus isolated in France. Electron microscopy observations revealed that the virions were icosahedral with a diameter of 33-35 nm, and with an average buoyant density of 1.33. Structural proteins were investigated by SDS-polyacrylamide gel electrophoresis and western blotting. The results indicated the presence of a major structural protein of 64 kDa and other minor proteins of molecular weight of 43, 36 and 32 kDa, the last presumably resulting from the proteolytic degradation of VP 64. These results correspond with the description made by the different authors who identify the VHD virus as a member of the Caliciviridae family.