The exact number of cetacean species present in Mauritanian waters is unknown. A first overview was published only in 1980, the latest in 1998. Yet, published information remains modest compared to e.g. neighbouring Senegal (first review in 1947). The complex oceanography of Mauritanian waters permits a mixed assemblage of cetacean fauna, with the distribution of both cool temperate and (sub)tropical species. In this updated review, we use our own observations from strandings, bycatches and vessel-based surveys, as well as published and grey literature, to support an inventory of cetaceans of Mauritania. The updated checklist includes two new authenticated species records: Kogia sima and Lagenodelphis hosei. Stenella coeruleoalba is verifiably documented for the first time. Further, a first specimen record of Stenella longirostris is presented, as well as new (second) specimens of Mesoplodon europaeus, Steno bredanensis and Megaptera novaeangliae. Revised evidence shows that of 30 reported species, 27 of 6 families are provably supported while 3 species lack (accessible) voucher material but probably (P) occur in Mauritania: Megaptera novaeangliae, Balaenoptera musculus, B. borealis, B. omurai, B. acutorostrata, B. physalus, B. brydei (P), Physeter macrocephalus, Kogia sima, K. breviceps, Sousa teuszii, Tursiops truncatus, Delphinus delphis, Stenella frontalis, S. attenuata, S. coeruleoalba, S. longirostris, S. clymene, Steno bredanensis, Peponocephala electra (P), Lagenodelphis hosei, Grampus griseus, Globicephala macrorhynchus, G. melas (P), Orcinus orca, Pseudorca crassidens, Ziphius cavirostris, Mesoplodon europaeus, M. densirostris and Phocoena phocoena. Finally, a first case of tattoo skin disease (TSD) is reported for continental NW Africa, in a stranded D. delphis.