Peritrichs attached to submerged macrophytes, filamentous chlorophytes and debries have been found in San Miguel del Monte pond (Buenos Aires province, Argentina) during the period March 1998- March 1999. Specimens were identified, illustrated and measured alive. Fourteen species of Subclass Peritrichia new for the country are described, illustrated and commented: Epistylis hentscheli, E. tubificis, E. vestita, Opercularia elongata, Cothurnia annulata, Cothurniopsis valvata, Pyxicola limbata, Thuricola innixa, Th. kellicotiana, Vaginicola attenuata, Vorticella picta, V. pulchella, V. rotunda and Zoothamnium ramosissimum