Philodendron geniculatum is described as a species new to science and illustrated. This species has been in cultivation for decades in the USA, Europe and Asia (Taiwan), but has not flowered until recently. It is characterised by a conspicuous geniculum on the apex of the subterete petiole, by an elliptic leaf blade with a thick, whitish midrib, many parallel primary lateral veins on each side, an auriculate base and a cuspidate apex, as well as by persistent red cataphylls drying brown soon and becoming fibrous later. P. geniculatum has a single inflorescence with a striking spathe, outside burgundy-red in the lower part and intensively red in the upper part. The species is morphologically closest and probably related to P. scherberichii, from which we delimit it.