A new citrus cultivar ‘Tamdosamho’ is a hybrid obtained from a cross of ‘Kiyomi’ (Citrus unshiu×Citrus sinensis, the seed parent) and ‘Sunburst’ (Citrus reticulate, the pollen parent) at the Citrus Research Institute of the National Institute of Horticultural and Herbal Science in 2004. ‘Tamdosamho’ had the first fruit set in 2010 and field evaluation has been conducted until 2012. The tree of ‘Tamdosamho’ was vigorous and had a lot of fruit bearing. The average fruit weight was 230g and its shape was flatten-oblate with a little neck. The fruit peel color was dark orange, and peel coloration began in mid-October and fully developed in early December. The fruit matured in mid-February from cultivation under plastic film house. Total soluble solid and acidity of which was 14.0 °Brix and about 1 % respectively. The thickness of the rind was about 2.5 mm on average and was thinner than that of satsuma mandarin (Citrus unshiu), so removing the peel was easy. This cultivar had characteristic of self-incompatibility and parthenocarpy and didn’t bear seeds from monoculture but if it be fertilized by the pollen of other cultivars could be seedy. In the case of cultivation in the open field, the fruits could be damaged by cold temperature and then ‘Tamdosamho’ is recommended for cultivation under plastic film house. (Variety registration number: 6158)