The Eastern Mediterranean Region has a significant potential for capia pepper production in Turkey. In the region, a population named as 'Karaisali pepper' with special characteristics, is grown. The population is well-adapted to the region and grown for processing. Karaisali pepper is usually preferred for red pepper production due to its high dry matter content. Survey studies conducted on Karaisali pepper in 2014 and 2015 demonstrated that the Tobacco etch virus (TEV) was the most common and destructive virus affecting Karaisali pepper. In the present study, three pure lines derived from Karaisali pepper were used to assess their susceptibilities against TEV. The experiment included mechanically inoculated infected plants and healthy pepper plants in the control group. The pepper plants were inoculated with the TEV using mechanical inoculation method during the four-leaf stage. The plants were observed periodically after mechanical inoculation. Each repetition was analyzed based on the total yield, pepper paste yield, fruit size, soluble solid content, fruit color and market value. The result indicated that, in average, TEV reduced Karaisali pepper yield by 77.5% and pepper paste yield by 33.6%. Furthermore, the average fruit length (37%), fruit diameter (21.4%), fruit wall thickness (14.2%), fruit volume (60.2%) and first quality fruit ratio were also decreased. The results confirm the threats of TEV in pepper production.