A $Mariannaea$ fungus was isolated during investigation of an elm tree infested with unidentified beetles. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA sequence, the fungus was identified as $Mariannaea$ $elegans$ var. $elegans$. Fungal growth was better on malt extract agar than on potato dextrose agar and oatmeal agar. Optimal temperature and pH for growth of the fungus were $30^{circ}C$ and pH 7.0, respectively. The fungus was found to have the ability to produce extracellular enzymes such as amylase, ${eta}$-glucosidase, cellulase, and protease. This is first report on $M.$ $elegans$ var. $elegans$ in Korea.