Lentinula edodes is an edible wild mushroom that can be found in mountainous regions of the Korean peninsula. Wild oak mushrooms were collected from Quercus mongolica at an elevation of more than 1,000 m on Mt. Jungwang and Mt. Gariwang in Gangwon province. We examined 10 oak mushroom strains to evaluate the genetic similarity among strains. Genetic similarity was determined based on the analysis of microsatellite markers (Led A2, Led A8, Led B2, Led B6, and Led D6) registered in the National Center for Biotechnology Information. We also performed dual culture tests on potato dextrose agar for 2 months at 25 °C. The observed heterozygosity across all microsatellites ranged from 0.00 and 0.60 among 5 microsatellite markers, and the polymorphism information content values of Led A2, Led A8, Led B2, Led B6, and Led D6 were 0.0000, 0.8144, 0.6194, 0.4892, and 0.5702, respectively (mean value = 0.4987). Confrontation lines between strains were formed for almost all combinations. In conclusion, the oak mushroom populations of Mt. Jungwang and Mt. Gariwang have mixed gene pools. However, further studies are needed to identify genetic similarities and variations among these populations.