Almost a fifth of voters switched allegiances as a result of the televised leaders' debates, according to a poll.
Some 17% said they changed their voting intentions after seeing Gordon Brown, David Cameron and Nick Clegg go head-to-head.
The findings are further evidence of the influence the first-ever televised leaders' debates had on the General Election campaign, following the Liberal Democrats' surge in popularity.
A Populus survey for strategic communications firm TLG also found that 45% of voters want the format to be repeated outside of general election campaigns, for example around key events such as the Budget or local and European elections.
And despite 2010 being hailed as the first "internet election", just 6% of people said online media had most influenced their decision on who to vote for.
Populus interviewed a nationally representative sample of 2,040 adults online on May 1 and 2.
