New records and new data are reported for fifteen species of Parmeliaceae s.str.. Cetrariastrum americanum (Mey. & Flot.) Culb. & Culb., Hypotrachyna sinuosa (Sm.) Hale and Parmelinopsis swinscowii (Hale) Elix & Hale are recorded for the first time from Argentina. Hypotrachyna densirhizinata (Kurok.) Hale and Flavoparmelia ferax (Mull. Arg.) Hale are confirmed for Argentina. Eight species are reported for the first time from Rio Negro and four from Neuquen (Northwestern Patagonian Provinces, Argentina). Ancillary information on Pannoparmelia angustata (Pers. in Gaudichaud) Zahlbr. emend Calvelo & Adler is furnished.