Onion purple blotch caused by the fungus Alternaria porri is a major yield limiting factor in Onion growingareas of Karnataka. A roving survey was conducted to assess purple blotch disease severity in onion during kharif 2016in North Eastern Karnataka. The disease severity ranged from 9.60 to 86.40 per cent. The highest disease severity wasnoticed in Garjanal village (86.40%) in Koppal district and the least disease severity was recorded in Dornahalli village(9.60%) in Yadgir taluk. It was concluded that, maximum severity in Koppal district might due to monocropping,prevalence of congenial micro climate, existence of initial inoculum and cultivation of susceptible varieties in larger scale.Out of 15 screened onion varieties mainly two varieties viz., Bheema Shakti and Bheema Super were found to havemoderate resistance by recording a disease severity of 18.92 per cent and 19.80 per cent respectively, Where as Bellaryred recorded highly susceptible reaction with disease severity of 74.86 per cent and hence it can be considered as fastblight cultivar.