Aristolochia brachylimba, a new species from Amazonian forests of Peru, is described, illustrated, and discussed with respect to its most similar species, A. stomachoidis Hoehne, from northern, central and eastern Brazil (Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Pará and Tocantins), and northeastern Argentina (Misiones). The new species differs from its relatives mainly by the size of the utricle, which is considerably larger than the short perianth limb, the conical shape of the tube (i.e. gradually narrowing down towards its distal end), and the winged, flattened seeds. So far, the new species has been found in Amazonian forests of two disjunct localities in Ataz (Oxapampa, Pasco) and the Cordillera Azul National Park (Ucayali, Loreto), at elevations between 340 and 479 m a.s.l.