Sequence analysis of a 795 nucleotide region of the fish rhabdovirus viral haemorrhagic septicaemia virus (VHSV) genome revealed one complete and one partial ORF of 369 and 153 nucleotides, respectively. The latter ORF probably encodes the amino-terminal part of the L (polymerase) protein. The former ORF potentially encodes a 122 amino acid protein. The location of this ORF as well as the size and deduced structure of the translation product indicate that it represents a homologue of the non-virion (NV) protein of the related infectious haematopoietic necrosis virus (IHNV). Antisera raised against prokaryotically expressed NV protein of VHSV and IHNV were used to detect NV expression in VHSV- and IHNV-infected cells by Western Blot and immunofluorescence analyses. We present here the sequence of the VHSV NV gene and demonstrate the presence of IHNV and VHSV NV proteins in virus-infected cells.