The Hato lagoon was sampled in three stations during a year, in order to determine the diversity of micro algae belonging to Chlorophyta, Cyanobacteria and Euglenophyta divisions, that contribute with scientific studies have been conducted to conserve this important aquatic ecosystem. Twenty eight species were identified. Chlorophyta was represented by 19 species, Euglenophyta by six and Cyanobacteria by three species. Seventeen new records to Nueva Esparta State were found, 11 species belong to Chlorophyta, five to Euglenophyta and only one species to Cyanobacteria. Cosmarium genus was the most representative micro algae.