The aim of this article is to describe two new setoid species of Marasmius: M. chrysoblepharioides and M. neotrichotus from the riparian forest of the Paraná river in Northeastern Argentina. Marasmius chrysoblepharioides is characterized by a sulcate-striate, yellowish orange pileus, an entirely pilose, orange brown stipe; caulosetae with a tapering and thick-walled apex, and its bacilliform to fusiform basidiospores. Marasmius neotrichotus differs from M. trichotus and M. ciliatus by its longer caulosetae and spores, respectively. The phylogenetic analyses based on molecular data from ITS sequences indicated that both new species are distinct from closely related species.