The Islamic Republic was followed by North Korea and Pakistan in the survey of negative and positive views of people in 27 countries based on events in 2010.
Iran saw its negative rating rise three points to 59 percent since the previous study, which was based on events in 2009.
Unfavourable ratings for Iran showed a marked year-on-year increase in Britain, Canada, the United States, Australia and the Philippines.
Germany was the most positively viewed nation, but Brazil was the big winner as its status as an emerging power was confirmed with a positive rating which rose from 40 percent to 49 percent, leaving it ranked seventh in the positive stakes.
In the year when it hosted the football World Cup, the proportion who rated South Africa positively rose to 42 percent from 35 percent last time.
Israel was ranked as the fourth most unpopular country.
The pollsters said that while views of Israel overall have not changed substantially over the past year, there had been “significant increases” in negative views of the country among Americans and Britons.
A total of 28,619 people were interviewed face-to-face or by telephone in December last year and on February 4 this year, meaning the survey was done before the overthrow of Egyptian president Hosni Mubarak.
The survey was carried out by polling firm GlobeScan together with the Programme on International Policy Attitudes (PIPA) at the University of Maryland.
