Main tobacco diseases were surveyed on major flue-cured leaf tobacco fields throughout South Korea in 2006. Mosaic caused by potato virus Y and bacterial wilt caused by Ralstonia solanacearum were most severe during harvest season. During last ten years, the damage by tobacco mosaic virus was reduced but the incidence of bacterial wilt increased. These changes of the disease incidences coincide with release time of the tobacco cultivar resistant to the tobacco mosaic virus but susceptible to bacterial wilt pathogen. Wild fire(Pseudomonas syringae pv. tabaci strain ungulate) occurred severely at Kangwon province, though the symptom of wild fire with yellow halo was not observed.