The Ephemeroptera fauna of Nicaragua is inventoried based on the study of recent collections and includes eight families, 28 genera, and 56 species. Forty-seven species are reported from Nicaragua for the first time. Genera found in Nicaragua for the first time include Allenhyphes Hofmann and Sartori, Baetodes Needham and Murphy, Camelobaetidius Demoulin, Choroterpes Eaton, Epiphrades Wiersema and McCafferty, Fallceon Waltz and McCafferty, Farrodes Peters, Guajirolus Flowers, Hagenulopsis Ulmer, Haplohyphes Allen, Lachlania Hagen, Leptohyphes Eaton, Maccaffertium Bednarik, Paracloeodes Day, Terpides Demoulin, Thraulodes Ulmer, Traverella Edmunds, Tricoryhyphes Allen and Murvosh, Ulmeritoides Traver, and Vacupernius Wiersema and McCafferty. Americabaetis alphus Lugo-Ortiz and McCafferty, Baetodes bibranchius McCafferty and Provonsha, Campsurus notatus Needham and Murphy, Fallceon planifrons (Kluge), Farrodes pakitza Domínguez, Molineri and Peters, F. savagei Domínguez, Traverella albertana (McDunnough), Tricoryhyphes condylus (Allen), and the genus Tricoryhyphes are reported from Central America for the first time.