Hedyotis, comprising about 150 species in the tropical and subtropical regions of the world and is one of the largest genera in Rubiaceae. Ten species were recorded in the 2nd edition of Flora of Taiwan. In the course of our botanical inventory, Hedyotis koana Wang, heretofore unknown in Taiwan, was collected from southern part of the island. Hedyotis koana is easily distinguished from other congeners by narrow leaves, terminal or upper axillary cyme and long flowering pedicles. In this report we provide a description, colored photographs and draw taken from the wild to aid identification.