In order to evaluate the impact of anthropogenic changes, such as the future construction of a dam at Adjarala, on the fish diversity of the Mono River basin, a list of the ichthyofauna of this basin has been compiled. This list was established based on data obtained from collections in natural history museums and from the literature, and updated following the most recent systematic revisions. A total of 60 native and one introduced species, belonging to 40 genera and 23 families, are reported. The families Cyprinidae and Cichlidae, with nine species each, are best represented in the list. Mormyridae, Alestidae and Clariidae account for six species each, while all other families contribute three species or less. Of the 60 native species recorded, three are typically marine, while five others are estuarine. Based on museum records, Raiamas senegalensis (Cyprinidae), previously not reported from the Mono basin, has been added. Earlier attributions of Marcusenius brucii, M. cyprinoides, Petrocephalus simus (Mormyridae), Labeo coubie (Cyprinidae), Brycinus leuciscus (Alestidae), Phractura ansorgii (Amphiliidae) and Synodontis melanopterus (Mochokidae) to the Mono basin proved to be based on misidentifications. The present study shows that the fish species diversity of the Lower Mono is most probably underestimated, due to inadequate sampling and the resulting lack of archived material from this portion of the basin.