A new subgenus and species of avian haemocytozoon Fallisia (Plasmodioides) neotropicalis is described. The principal characteristics are the main host cells, thrombocytes and mononuclear leucocytes, where trophozoites, schizonts and gametocytes are found. Occasionally, granulocytes and very rarely reticulocytes are also parasitized. Phanerozoites very similar to those of Plasmodium of birds are also present. The host is the domestic pigeon, Columbalivia, an imported species but similar parasites have been identified, always mixed with species of Plasmodium, in several indigenous species of Ciconiiformes, which seem to be the natural hosts. This is the first report in birds of a representative of the genus Fallisia, parasites of neotropical lizards.