The number of people who see Brazil as having a positive influence in theThe country is now regarded positively by 49%, compared to 40% last year - the largest jump by any of the 16 nations respondents are asked to comment on.
South Africa, host of the 2010 World Cup, posted the second biggest rise.
Germany remained the most popular country, while the image of the US improved for the fourth year in a row.
The UK achieved the second highest positive rating, continuing a steady rise in its fortunes since 2006.
More than 28,000 people across the world were interviewed between December 2010 and February 2011 by international polling firm GlobeScan and the Program on International Policy Attitudes (Pipa) at the University of Maryland.
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"The growing credibility of middle powers is the story this year, especially Brazil and South Africa," said GlobeScan chairman Doug Miller.
"The jump in positive views of Brazil follows the successful democratic transition from President [Luiz Inacio] Lula da Silva to Dilma Rousseff, Brazil's first female president."
Views of the country were predominantly positive in all but two of the 27 countries - China and Germany.
In China, 45% rated Brazil's influence as positive, but only marginally fewer, 41%, rated it negatively.
In Germany the proportion of those polled who rated Brazil's influence negatively - 32% - slightly exceeded the 31% who rated it positively.
In general Brazil is regarded very favourably in the American countries polled - the US, Canada, Brazil, Chile, Peru and Mexico - and in all Western European countries included in the survey, apart from Germany.
Views of Brazil in two fellow members of the Bric group of countries - Russia and India - are less negative than they are in the fourth members of the group, China, but still only lukewarm. Most respondents in both countries said they were neutral towards Brazil, or offered no opinion, but only 29% in India and 37% in Russia had a positive view.
Positive views of South Africa's influence jumped from 35% to 42% overall, with big improvements in the US and Canada, Spain, Italy, Turkey, Egypt and South Korea.
Overall, positive ratings increased for 13 of the 16 nations respondents were asked to rate.
"While last year relatively dour views of nations were prevalent - perhaps reflecting the mood of the economic downturn - the mood now seems to be relatively upbeat," said Pipa director, Steven Kull.
US recovery
The average ratings of the three most negatively viewed countries - Iran, North Korea and Pakistan - went from bad to worse, however.
In 2007, the US was among the countries with the lowest ratings, but it has climbed quickly up through the rankings since then.
Focusing on polling results from 15 countries where the survey has been carried out every year since 2005, positive views of the US outnumbered negative views in 2010 for the first time, and are now 12 points clear. That leaves the US roughly in the middle of the league table of 16 countries.
The most negative views of the US are found in majority-Muslim countries, though opinions in Indonesia have undergone a marked shift in the last year, with positive views of US influence, at 58%, now more than twice as prevalent as negative views (25%).
In Turkey views remained negative overall, but there was a 22-point increase in positive views (now 35%) and a 21-point drop in negative ratings (now 49%).
In Egypt, however, while views of the US improved in 2010, they tumbled again this year. In the 2011 survey - carried out before the revolution that toppled President Hosni Mubarak - negative views rose 21 points to 50%, while positive views dropped 19 points to 26%.
