Oyster mushroom is one of the most widely cultivated and consumed mushrooms in Korea, and mechanization and automation of cultivation systems have enabled mass production. Many cultivars have been developed to replace the old ones such as ‘Suhan‘ and ‘Chunchuneutari 2 ho,‘ which have been cultivated for over 20 years. Among these, ‘Soltari‘ was developed in 2015. Although it has excellent quality, its cultivation is challenging and the productivity is somewhat lower. To address these issues, the Mushroom Division at the National Institute of Horticultural and Herbal Science selected the genetic resource KMCC05165 and attempted hybridization between monokaryons from KMCC05165 and ‘Soltari(KMCC04940)’. Through repeated cultivation tests and evaluation of fruiting body characteristics, the superior strain ‘Po-2019-smj22’ was selected and finally named ‘Otari‘. The optimal mycelial growth temperature of ‘Otari’ was between 25 and 30°C and optimal fruiting body growth temperature was between 13 and 18°C. Mycelial growth on PDA medium was best at 25°C, and at the same temperature, mycelial growth was similar across four media: PDA, MEA, MCM, and YM. In 1,100 mL bottle cultivation, the yield was approximately 174 g, which is about 5% higher than the control cultivar ‘Soltari‘, and the number of valid individuals was also higher at about 25. The diameter and height of the pileus were 29.8 mm and 17.6 mm, respectively, slightly smaller than ‘Soltari‘, and the stipe was thin and long with a thickness of 12.2 mm. Additionally, the pileus’ lightness index (L index) was 30.7, indicating a darker brown color compared to 'Soltari.' With excellent mycelial growth, ease of cultivation, and high yield, the new cultivar ‘Otari‘ is expected to be widely adopted by domestic oyster mushroom farms.