Inthispapertheexistenceanduniquenessofthesolutionofimplicithybridmethods(IHMs)forsolvingtheinitialvalueproblems(IVPs)ofstiffordinarydifferentialequations(ODEs)isconsidered.Weprovidethecoefficientconditionanditsjudgingcriterionaswellastherighthandconditiontoensuretheexistingsolutionuniquely.