In comments posted on Twitter, Rousseff lent her support to former Brazil international midfielder Arouca, who was racially abused by a fan while representing Santos against Mogi Mirim in the Sao Paulo state championship March 6, Xinhua reported Monday.
"It's inadmissable that Brazil, the country with the largest black population out of Africa, has racism issues," Rousseff said.
Last week's incident came a day after racist chants were directed at referee Marcio Chagas da Silva during the Rio de Janeiro state championship match between Esportivo and Veranopolis.
Rousseff also pledged to make the anti-racism message a theme of this year's World Cup.
"We are going to take on racism. We have agreed with the UN and FIFA that this will be a World Cup against racism."