ABSTRACT Present study aimed at carrying out the taxonomic survey of the ornamented cell-wall Cosmaria from the low Doce river region, Espírito Santo State. Material studied was collected between months October 2018 and February 2020. Thirty-three taxa were identified, from which 32 are new additions to the Espírito Santo State desmid flora, five are new records for Brazil (C. blyttii cf. var. basiornatum, C. cf. dentiferum, C. monomazum var. polymazum, C. sphagnicola var. pachygonum, and C. subcostatum var. subcostatum), and one for South America (C. isthmochondrum cf. var. biseriatum). Present study increased the knowledge on the genus Cosmarium in Espírito Santo State by adding both taxonomic and ecological information.