Leafroll is one of the most important virus diseases of vineyards of Central Anatolia region. Grapevine leafroll associated viruses GLRaV-1 and GLRaV-3 are the most frequently encountered viruses related with leafroll disease of grapes. The effect of leafroll disease on yield and fruit quality was studied. The disease caused in the average 31.22% decrease of berry weights and 28.72% reduction in total soluble solids, while titratable acidity was increased by 24.39%. The reaction of local cultivars to mixed infections of GLRaV-1 and GLRaV-3 was evaluated and Parmak, Kara dirmit, Kara gevrek and Gul uzumu cultivars were considered to be the most sensitive local cultivars to GLRaV-1 and GLRaV-3.