A new species, Philodendron montemariense Croat, J. J. Percy & Carrascal, is described from the Reserva Forestal Protectora Serranía de Coraza, in the department of Sucre, Colombia. The species is a member of subgenus Philodendron, section Philodendron, series Fibrosa Croat. It is most similar to P. asplundii Croat & M. L. Soares, but has stems with fewer persisting cataphyll fibers and more broadly ovate leaf blades, which typically dry gray above and grayish yellow-green below, and which have fewer primary lateral veins that are undulated on the upper surface when dried.