Two new earthworm species of the genus Polypheretima Michaelsen, 1934, are described from Song Thanh Nature Reserve, Quang Nam Province, in the southern region of central Vietnam. Both new species belong to the bifaria species-group, which are characterised by holandry and having simple male pores and intersegmental spermathecal pores. Polypheretima medialis, new species, is distinguished by having two pairs of spermathecal pores in 7/8/9, and genital markings ventrally paired in viii–ix and xvii–xix; while P. tabhinhensis is distinguished by having three pairs of spermathecal pores in 6/7/8/9, rectangular genital markings which are raised on the body wall, and paired in ix–x and the male region. An identifcation key to the Vietnamese species of Polypheretima is also provided