This is the first revision of the genus Chlorospatha Engl. (Araceae) since Michael Madison's 1981 treatment. The genus consists of three sections, two of which are newly established: Chlorospatha sect. Occidentales Croat & L. P. Hannon and Chlorospatha sect. Orientales Croat & L. P. Hannon. Included are 69 taxa (68 species and one variety) for Central and South America, of which 45 are new to science. These include 39 newly described species: C. bayae Croat & L. P. Hannon, C. boosii Croat & L. P. Hannon, C. bullata Croat & L. P. Hannon, C. caldasensis Croat & L. P. Hannon, C. caliensis Croat & L. P. Hannon, C. carchiensis Croat & L. P. Hannon, C. cedralensis Croat & L. P. Hannon, C. chocoensis Croat & L. P. Hannon, C. congensis Croat & L. P. Hannon, C. engleri Croat & L. P. Hannon, C. giraldoi Croat & L. P. Hannon, C. grayumii Croat & L. P. Hannon, C. hannoniae Croat, C. hastata Croat & L. P. Hannon, C. huilensis Croat & L. P. Hannon, C. jaramilloi Croat & L. P. Hannon, C. limonensis Croat & L. P. Hannon, C. litensis Croat & L. P. Hannon, C. longiloba Croat & L. P. Hannon, C. maculata Croat & L. P. Hannon, C. mansellii Croat & L. P. Hannon, C. morae Croat & L. P. Hannon, C. munchiquensis Croat & L. P. Hannon, C. nambiensis Croat & L. P. Hannon, C. narinoensis Croat & L. P. Hannon, C. noramurphyae Croat & L. P. Hannon, C. oblongifolia Croat & L. P. Hannon, C. portillae Croat & L. P. Hannon, C. pubescens Croat & L. P. Hannon, C. queremalensis Croat & L. P. Hannon, C. risaraldensis Croat & L. P. Hannon, C. sagittata Croat & L. P. Hannon, C. sizemoreae Croat & L. P. Hannon, C. stellasarreae Croat & L. P. Hannon, C. sucumbensis Croat & L. P. Hannon, C. timbiquensis Croat & L. P. Hannon, C. tokioensis Croat & L. P. Hannon, C. yatacuensis Croat & L. P. Hannon, and C. yaupiensis Croat & L. P. Hannon. Four additional and putative new species are described in detail at the end of the taxonomic treatment and are included in the key, but not formally named; they are labeled Species 1 to 4 and are assumed to be new. They were collected as sterile plants and will be formally described only after recollection in fertile condition. Two combinations are made: C. plowmanii (Madison) Croat & L. P. Hannon and C. croatiana Grayum var. enneaphylla (Grayum) Croat & L. P. Hannon. Species diversity of Chlorospatha is greatest in the Andes of Colombia and the western Andes of northernmost Ecuador, and diminishes from northernmost Colombia into Central America and from central Ecuador southward to the border with Peru. Costa Rica has two taxa (one species, one variety), Panama four taxa (three species, one variety), Colombia 45 taxa (44 species, one variety), and Ecuador 24 species. Endemism is highest in Colombia, with 43 species currently considered endemic, followed by Ecuador with 23 endemic species, and Central America with two endemic species.