Two new species, Eriocaulon cylindratum and Eriocaulon araguaiense, from the Tocantins-Araguaia River basin in the Brazilian Cerrado, are described and illustrated. The species are similar, but they differ mainly in both the shape of the capitula and the
floral bracts. Eriocaulon araguaiense has hemispheric heads, and obovate, concave floral bracts. Eriocaulon cylindratum is characterized by ovoid or cylindrical heads, and obtrullate, carinate floral bracts. A key to all known Eriocaulon species from Tocantins-Araguaia
river basin is presented.