Varroa destructor is an ecto-parasite mite and worldwide pest of the honey bee Apis mellifera L. The pyrethroid tau-fluvalinate (Apistan), an acaricide that is tolerated by honey bees, has been used for varroa mite control since the mid 1980s. Even though various resistances to tau-fluvalinate in varroa mites have been reported from Europe, Israel, and USA, the nature of tau-fluvalinate resistance in varroa mites in Korea has never been investigated. To investigate and understand tau-fluvalinate resistance in varroa mites in Korea, we conducted bioassay in several apiaries located different regions in Korea. To understand the molecular mechanisms underlying the difference of tau-fluvalinate resistances in varroa mites, partial genomic DNA fragments of a voltage-sensitive sodium channel gene from varroa mites were cloned and sequenced, since tau-fluvalinate is known to act on the sodium channels directly. Two novel mutations in sodium channels of varroa mites were present in eight apiaries. Two mutations might be a geographical polymorphism of sodium channel of varroa mites in Korea.