PALYNOSTRATIGRAPHY OF SALTO DEL MACHO FORMATION, PALEOGENE OF THE ÑIRIHUAU BASIN, ARGENTINA. The complete record of the palynomorphs from the Salto del Macho Formation (Paleogene) is presented from its type locality at the Foyel River section, Ñirihuau Basin Andean area, Argentina. Elements of continental and marine origin were identified: a total of 109 species corresponding to Bryophyta, Lycopodiophyta and Polypodiosida spores, Gymnospermophyta and Magnoliophyta (Angiospermae) pollen grains, continental algae and marine organic-walled microplankton. The stratigraphic distribution of sporomorphs recognized in the Salto del Macho Formation at other Paleogene—early Neogene (Miocene) basins from Patagonia argentina, Chile and Antarctica is presented. The presence of Echitriporites trianguliformis form A Müller et al., Psilatricolpites minutus González Guzmán, and Myrtaceidites parvus form nesus Cookson and Pike at the Salto del Macho Formation represents the first record of these species in Argentina. An age comprised between middle Eocene and early Oligocene is here suggested for this unit, on the basis of data yielded by palynological markers and palynostratigraphic and multivariate analyses.