We recorded Myoxanthus xiphion for the first time in Colombia from a population found in the Andean-Amazonian Foothills of the department of Caquetá, at 1075 m a.s.l., 260 km to the north from the known populations in Ecuador. With this species, the genus Myoxanthus reaches 18 species in Colombia, most of them growing in the Andes. For the Colombian Andean-Amazonian Foothills five Myoxanthus species are recorded, including M. xiphion, distributed in the departments of Caquetá, Cauca, Nariño and Putumayo. Myoxanthus xiphion was known before only in Bolivia and Ecuador, but its distribution may be extended throughout all the Andean-Amazon Foothills from Bolivia to Colombia. We present a description of M. xiphion, photographs, a map with the populations recorded until today, and a key to identify the Myoxanthus species of the Andean-Amazonian Foothills from Colombia.