During the past years tobacco losses caused by virus infection showed a global aggravation of PVY invasion in Bulgaria. The study was carried out during 1993-95 in the greenhouse of the Tobacco Institute and in the experimental fields of the Tobacco Exp. Sta. in Gotze Delchev and Rila. The susceptibility of tobacco varieties grown in different regions of the country was studied after artificial mechanical inoculation of plants at different phenological stages. PVY accumulation was checked by DAS-ELISA. The negative effect of early PVY infection was the most prominent on the varieties from the Dupnitza and Necrokop origins and resulted in reduced yield and quality of the tobacco raw material.