Based on collections performed between 2008 and 2009 at Parque Nacional do Caparaó, Reserva Biológica de Sooretama, among other areas in Espírito Santo State, southeastern Brazil, we present the first survey of mayflies (Insecta: Ephemeroptera) from the state. Despite the fact that the state is one of the smallest in Brazil, representing only 0.53% of the country area, a surprising diversity was found. Seventy-...