Paradiplozoon cirrhinin. sp. (Monogenea, Diplozoidae) is described from the gills of mud carp,Cirrhinus molitorella(Valenciennes, 1844) (Cyprinidae, Labeoninae), collected in Wuzhou, Guangxi Province, and Conghua, Guangdong Province as part of an ongoing survey of the diplozoid fauna in the Pearl River basin of China. The newParadiplozoonspecies is distinguished from congeners by the structure of median plate and its outgrowth sclerites. The ITS2 sequences of the new species differ from all known available diplozoid sequences by 22.04%–38.34%. The new species is the first diplozoid species parasitic on Labeoninae in China. Molecular phylogenetic analyses using rRNA ITS2 placedParadiplozoon cirrhinin. sp. in a sister position to the other ChineseParadiplozoon, implying that Labeoninae represents an early and potentially ancestral host group for ChinaParadiplozoon. We also provided ITS2 sequences for four other diplozoids species, namelyP. megalobramaeKhotenovsky, 1982,P. saurogobionis(Jiang,et al., 1985) Jiang, Wu & Wang, 1989,Sindiplozoon hunanensisYao & Wang, 1997, andSindiplozoonsp., and validated their phylogenetic position. The results confirm that all diplozoid species are spilt into two major clades and show monophyly ofSindiplozoonbut paraphyly ofParadiplozoon.