Although ear mushroom (Auricularia auricula-judae) is cultivated worldwide, there are a limited number of commercial cultivars in Korea. Recent increase in the import of ear mushroom from China threatens the domestic farming. The present study introduces a new thermotolerant cultivar of ear mushroom, designated ‘Hyeonyu’, developed by mating monokaryons obtained from JBAA11 and CAA1 strains. The optimal growth temperature for Hyeonyu was 26-36?. The periods of primordia formation and fruit-body growth were 27 and 15 days, respectively. The average mushroom yield per bag (1 kg) was 350 g. Random amplification of polymorphic DNA (RAPD) analysis with OPA1 and OPA7 primers identified polymorphic DNA bands between the control, the new variety Hyeonyu, and a Chinese variety.