Of the 3,810 respondents of both sexes who responded to the government's Institute of Applied Economic Research (IPEA) survey released this week, about 2,480 -- 65 per cent -- justified raping women who wear "clothing that shows off the body."
And 58.5 percent of respondents also agreed that "if women knew how to behave, there would be fewer rapes."
Most of the May-June poll's respondents -- 66.5 percent -- were women.
Journalist Nana Queiroz launched an online protest event on Facebook that invited women to take pictures of themselves topless while covering their breasts accompanied with the phrase: "I don't deserve to be raped."
Around 2300 GMT yesterday, about 20,000 women simultaneously posted their photographs online.
Results were posted on the Tumblr microblogging platform at naomerecoserestuprada.Tumblr.Com.
Queiroz, 28, said she received several threats of rape while she led the protest online.
"The most surprising thing is that it is permissible to walk naked in the Carnival, but not in real life," Queiroz told AFP.
President Dilma Rousseff also criticised the poll's results, saying the government-run study shows that "Brazilian society still has a long way to go."
"It also shows that the government and society must work together to tackle violence against women inside and outside the home," she said on her Twitter account.
