In this study, we report the occurrence of four domestic mushrooms (among 317 samples) that were previously undocumented in the eastern part of Jeju Island in Korea. To identify the mushrooms, DNA sequences of the mushrooms were analyzed by comparing them with the data available in NCBI GenBank. Mushrooms were identified as Agaricus flocculosipes, Amanita concentrica, Coprinopsis strossmayeri, and Favolus acervatus, none of which have been previously documented in Korea. Furthermore, microscopic observations revealed that the morphology of the four mushrooms was consistent with the features of the species matched by the DNA sequences analysis.