Two PVY strains (PVY-VB and PVY-VN) isolated from tobacco in Korea were compared for their serological relationship with other 8 strains which were obtained from tobacco or potato in different countries. One of these strains, PVY-Argentina showed the spur reaction to PVY-VB and PVY-VN antisera in SDS-agar gel double diffusion plates. The two Korean PVY strains were closely related to other strains except for one, PVY-Argentina when antigen-antibody reciprocal absorption tests were conducted. It is suggested that the strain, PVY-Argentina, is a new serotype containing a specific antigenic site different from other 9 strains tested.