The terminal regions of the dsRNA genome segments of rice black streaked dwarf virus (RBSDV) were sequenced. The individual dsRNAs, which were 32P-labelled at their 3' termini by incubation with [32P]pCp and T4RNA ligase, were separated by 5% PAGE, and the 10 dsRNA segments were sequenced by two-dimensional electrophoresis. The common 3'-terminal sequences ---GUC 3' and ---AAAAACUU 3' were found in the plus and minus strands, respectively. The strictly conserved terminal sequences (5' AAGUUUUU ... GUC 3') of the genome segments of RBSDV differ from those of the phytoreoviruses and rice ragged stunt virus.