A peak audience of 7.6 million viewers watched Oxford win the 154th Boat Race, sponsored by Xchanging, live on ITV1 on Saturday.
The figure makes it the most-watched race since ITV began broadcasting the event in 2005.
An average of 4.4 million watched ITV's entire coverage from 4-6pm, presented by Craig Doyle.
Oxford won in 20mins 53 secs - the slowest time since 1947 - six lengths ahead of Cambridge.
"We are very pleased with the figures," said Giles Vardey, chairman of race organisers BRCL.
"They show that the race is still a very big draw to millions of people who appreciate sport at its purest and its best.
"That's what we provide, combined with ITV's high-quality coverage."
In spite of the bad weather, thousands of spectators headed for the banks of the Thames to watch the famous race.
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