Twister disease of onion has become epidemic in coastal tract and other onion growing districts of Karnataka which caused heavy loss and its causal agents are C. gloeosporioides and F. oxysporum . Efforts were made to screen fungicides to know their efficacy of different fungicides at different concentrations under In vitro by poisoned food technique. Among the four non-systemic fungicides evaluated against C. gloeosporioides maximum inhibition was observed in chlorothalonil (42.60%). Among the seven systemic fungicides against F. oxysporum evaluated, hundred per cent inhibition of mycelial growth of C. gloeosporioides at all tested concentrations was observed in propiconazole, hexaconazole, tebuconazole and tricyclazole. Among the seven combi product fungicides evaluated carbendazim 12 per cent + iprodione 63 per cent (Quintal) inhibited maximum mycelial growth (95.43%). In vitro evaluation of fungicides revealed that among the four non-systemic fungicides evaluated, maximum inhibition of mycelial growth of F.oxysporum was observed in copper oxychloride (64.84%). Among six systemic fungicides evaluated, maximum inhibition of mycelial growth of F. oxysporum was observed in propiconazole (93.52%). Among the six combiproduct fungicides evaluated, hundred per cent inhibition of mycelial growth was observed in Saaf, Sprint and Vitavax power at all tested concentrations.