Twelve taxa of the genus Chara (Characeae, Chlorophyta) are decribed and illustrated based on specimens from southern Brazil. The taxonomic survey in the states of Paraná, Santa Catarina and Rio Grande do Sul recorded seven, one, and nine species for each state, respectively. Chara guairensis was the most common species in the area, followed by C. rusbyana. The species Chara guairensis, C. martiana, C. rusbyana, Chara hydropitys, C. braunii and its varieties were recorded for the first time in Rio Grande do Sul, and the following six for Paraná: C. angolensis, C. diaphana, C. guairensis, C. kenoyeri, C. martiana, and C. zeylanica.