158 craniodental and about 50 postcranial specimens of suids have been excavated from Arrisdrift, southwestern, Namibia, Two species are represented in the sample, Namachoerus moruoroti (121 craniodental specimens) and Nguruwe kijivium (37 craniodental specimens), both of which also occur in early and basal Middle Miocene sites in East Africa, In East Africa these species have not yet been found in the same localities, N. kijivium being confined to Faunal Sets PI and P1/ (ca 20-17.5 Ma), whereas N. moruoroti is recorded from Faunal Set PIIIa (17.2-16 Ma). Their co-occurrence at Arrisdrift suggests an age of ca 17.5 Ma for the Namibian site. The Arrisdrift sample of N. moruoroti is far more comprehensive than any of the East African collections of the species and throws a great deal of light on the its cranial and dental anatomy. N. moruoroti may have descended from the diminutive kubanochoere Nguruwe namibensis (ca 21 Ma) by increase in lophodonty, outward bowing of the base of the mandible and slight increase in size. The lineage is not close to Listriodontinae as previously thought, and it did not give rise to Lopholistriodon. The sample of Nguruwe kijivium from Arrisdrift is the best known of the species, but it is dominated by juvenile specimens. In all material respects the Namibian Nguruwe kijivium fossils accord well with samples from East Africa and any doubts about conspecificity that there may have been can now be removed.