A new mandarin hybrid cultivar ‘Shinyegam’ was developed from a cross between ‘Kiyomi’ (Citrus unshiu × C. sinensis) and ‘Wilking’ (Citrus reticulata) at the Citrus Research Institute of the National Institute of Horticultural and Herbal Science in 2012. The ‘Jegam na No. 33’, a first selection seedling from the fruits obtained in 2008 was finally named ‘Shinyegam’ after field evaluation trials at five locations in Jeju island, Korea from 2010 to 2012. The tree vigor was intermediate and the tree was spreading in nature, similar to that of the ‘Kiyomi’ cultivar. The fruits produced were compressed to oblate and globose in shape, were a deep orange in color, and moderately weighed at 130 g. ‘Shinyegam’ produces fruit that mature in late December, and has few seeds, which are mono-embryonic. The average seed number of a fruit varied depending on the pollinator citrus tree. Cultivation of ‘Shinyegam’ along with the other cultivars possessing high pollen fertility resulted in seed numbers that was more than 20, while in the absence of a pollinator species the seed number was around 5. The fruit contained soluble solids at 11 to 12 ° Bx and the acidity was approximately 1% at maturity. The rind thickness of approximately 2.5 mm ensures easy peeling. The flesh is very tender and juicy, with a pleasant, aromatic flavor similar to that of ‘Wilking’ but is comparatively weak. ‘Shinyegam’ is moderately resistant to the citrus scab disease and melanose, but susceptible to citrus canker. Owing to the high quality of fruit, good aroma, and cold hardness characteristics, this cultivar is expected to satisfy consumer acceptability in terms of the diversity of the cultivar in open-field cultivation.