The neotropical Cladoniaceae comprises 184 known species in four genera: Cladia, Cladina, Cladonia, and Pycnothelia. Twenty-nine new taxa and six new combinations are described. Many previously described taxa are reduced to synonymy. Keys are provided for the species. Synonymy, typifications, descriptions, secondary chemistry, distribution maps, habitats, economic uses, and a selection of herbarium voucher specimens are given for each species.