A process for regenerating a used ionic liquid catalyst comprising a cationic component and an anionic component, which catalyst has been deactivated by conjunct polymers complexed with the anionic component comprising the steps of adding a reagent which is capable of replacing the complexed conjunct polymer with the cationic component of the catalyst, said reagent being added in an amount sufficient to react with a suitable amount of both free and complexed anionic components in the used catalyst and removing the replaced conjunct polymer to produce a regenerated ionic liquid catalyst is disclosed.