A list of fishes collected in the N’sele River, a large affluent tributary of Pool Malebo, in the Democratic Republic of Congo is provided. Sites along the main channel and its affluent tributaries were sampled and 148 species distributed in 27 families are reported. Despite close proximity to the megacity of Kinshasa, the ichthyofauna of the N’sele River has not previously been documented, and in the course of the current study, 19 of the 148 species are recognized as new records for the region. Due to difficulties of access much of the middle reach of the N’sele River remains to be inventoried and, while the present report documents high diversity in this system, the list is likely to be incomplete. Although preliminary, the current report provides a solid foundation for further work in a region that is undergoing rapid environmental degradation.