We provide new records for 14 species of Odonata and two species of Ephemeroptera including two new records for Argentina: Nephepeltia leonardina Racenis (Anisoptera: Libellulidae) and Alloretochus peruanicus (Soldan) (Ephemeroptera: Caenidae). The distributions of Aphylla theodorina (Navas) (Anisoptera: Gomphidae) and Caenis tenella (Navas) (Ephemeroptera: Caenidae) are extended to the Yungas (both previously known for the NE of Argentina). New records are also included for: Neoneura confundens Wasscher & Van't Bosch (Coenagrionidae); Anax amazili (Burmeister) (Aeshnidae); Brachymesia furcata (Hagen), Erythemis plebeja (Burmeister), Erythrodiplax melanorubra Borror, E. nigricans (Rambur), Macrothemis imitans imitans Karsch, M. musiva Calvert, Miathyria marcella (Selys) and Micrathyria hesperis Ris (Libellulidae); Progomphus complicatus Selys and Progomphus joergenseni Ris (Gomphidae).