A hitherto uncharacterized nucleoprotein sedimenting at 95S-99S was observed in preparations of 6 different isolates of strawberry latent ringspot virus when centrifuged in sucrose-density gradients. This component had the same coat protein composition, serological properties, size and outward aspect of particles as the rest of the virus and encapsidated a molecule of RNA-2, thus exhibiting all major characteristics of the middle (M) component of nepoviruses. One of the virus isolates under study and 2 functional RNA species, appeared to possess a 3rd satellite-like RNA with MW 0.45 .times. 106.