Four new Chiloplacus spp. are described from South West Africa/Namibia, all of which have five incisures in the lateral field. C. tenuis n. sp. which is compared with C. saccatus Loof, 1971 and C. quinquesulcus Ivanova, 1968 is distinguished by deeply bifurcate labial probolae with recurved apical ends, toughing each other, C. subtenuis n. sp. resembles C. kralli Bagaturija, 1973 but differs by having only five instead of six lateral lines, as well as the presence of a postvulval sac. C. longiuterus n. sp. differes from C. bathycolpus Andrassay, 1967 and C. quinquesulcus by the longer postvulval sac, the shape of the spicules (only slightly arcuate ventrally) and the distribution of caudal papillae. C. magnus n. sp. differs from C. propinquus (De Man, 1921) Thorne, 1937, by having five lateral lines, a large postvulval sac, and presence of males. The male of Macrolaimellus longicauda (Rashid, Geraert & Sharma, 1985) Rashid & Geraert, 1987 is described here for the first time.