Manihot cezarii M. Martins (Euphorbiaceae) is described and illustrated from the states of Goiás and Mato Grosso, Brazil. This species has flat, greenish blue leaves and pendent inflorescences with foliaceous bracts, characteristics that distinguish it from M. alutacea D. J. Rogers & Appan. The conservation status of the new species is assessed as Endangered (EN), according to IUCN Red List criteria.