Morphological analysis of anopheline mosquitoes from Kasane, Botswana, revealed a new species, Anopheles seretsei, that is closely related to Anopheles azevedoi and Anopheles listeri. A description of the type locality and biological characteristics of An. seretsei is given. Comparisons are made with An. listeri and An. azevedoi. The banding patterns of the giant polytene chromosomes of An. seretsei were compared with those of An. listeri and found to be homosequential.