Weberbauera arequipa Al-Shehbaz & Montesinos (Brassicaceae), a new species from Peru, is described and illustrated. It is distinguished from the other species of Weberbauera Gilg & Muschler by having ebracteate racemes, persistent sepals and petals, 4-seeded fruits, and a few simple trichomes restricted to the petiolar bases. It is closely related to the Bolivian W. retropila Al-Shehbaz, but differs by the lack of branched trichomes and by having glabrous fruits, smaller flowers, and persistent petals. The IUCN status of the new species is determined as Data Deficient (DD). © Missouri Botanical Garden 2009.