Redefinition of the genus Willinema is based on paratypes of the type species W. parvum (Williams, 1959), and on four new species. W. laopangense n. sp. resembles the type species, but differs in shape of the vaginal sclerotization. W. paraparvum n. sp. is also close to W. parvum and W. laopangense, but differs in having a pseudomonodelphic to didelphic female reproductive system and common occurrence of males. W. nanum n. sp. is a small species with small vaginal sclerotization. It resembles W. eburnense n. sp. in the swollen, offset lip region, but both species clearly differ in body size and shape of vaginal sclerotization. W. indicum Baqri & Jairajpuri, 1967 is excluded from the genus. A key to the species is given. © 1984, Brill. All rights reserved.