One new species of Naidinae (Oligochaeta, Naididae), Naisbadia sp. n. and one new record species from China, Tubifexmontanus Kowalewski, 1919 (Tubificinae) are found in southern Tibet. The new species is distinguished from congeners by its large area of reddish brown pigment in the anterior segments I-VIII, serrate hairs, pectinate needles with 1-2 intermediate teeth, ventral chaetae partly with 1-2 fine intermediate teeth and wave-like movements. The new material of the species Tubifexmontanus differs slightly from the previous descriptions by its vas deferens entering atrium subapically, wide ental end of penial sheath and smooth hair chaetae.
Keywords: Naididae; Naisbadia; Tubifexmontanus; new record species; new species; southern Tibet; taxonomy.