Thursday night's debate focused on the economy
An average audience of 8.4m people watched the BBC's prime ministerial debate, early overnight figures show.
At 2100 BST, a peak of 9.1m viewers watched the last of three TV debates featuring Gordon Brown, David Cameron and Nick Clegg.
The figures cover simultaneous live screenings on BBC One, BBC HD as well as the BBC News and Sky News channels.
An average of 9.4m viewers tuned into the first ITV1 debate a fortnight ago, while 4m watched last week's Sky event.
Thursday night's coverage was up against Coronation Street on ITV1, which attracted an average 6.7 million, while the Uefa Europa League game between Liverpool and Atletico Madrid on Five drew 3.4 million.
Topics discussed in the 90-minute debate, hosted by the BBC's David Dimbleby in Birmingham, included spending cuts, immigration, housing and banking reform.
Snap polls suggested viewers felt the Tory leader was the winner.