A new freshwater goby, Rhinogobius immaculatus sp. nov., is described here from the Qiantang River in China. It is distinguished from all congeners by the following combination of characters: second dorsal-fin rays I, 7-9; anal-fin rays I, 6-8; pectoral-fin rays 14-15; longitudinal scales 29-31; transverse scales 7-9; predorsal scales 2-5; vertebrae 27 (rarely 28); preopercular canal absent or with two pores; a red oblique stripe below eye in males; branchiostegal membrane mostly reddish-orange, with 3-6 irregular discrete or connected red blotches on posterior branchiostegal membrane and lower operculum in males; caudal-fin base with a median black spot; and no black blotch on anterior part of first dorsal fin in males.
Keywords: China; Gobiidae; New species; Qiantang River; Rhinogobius.