The British actress won the title with 18% of the vote, beating out a number of female celebrities including Elle Macpherson, Jennifer Lopez and Pippa Middleton, People reports.
Meanwhile, among the men, new father David Beckham was crowned the champion with 21% of the vote, followed by James Bond star Daniel Craig and Pirates of the Caribbean's Johnny Depp.
The survey is commissioned every year by the LA Fitness gym chain.
In April, Mirren revealed that she would not be watching the royal wedding of Prince William and Kate Middleton after failing to secure an invite to the highly-anticipated event.
The Arthur star previously said that she is ''very comfortable'' with her sexuality, insisting that women do not lose their sex appeal as they get older.