The deal, brokered by MindShare Interaction Worldwide, is one of the biggest commercial deals struck by BBC Worldwide since it was given BBC Trust approval to carry advertising on BBC.com last November. Launch advertisers for BBC.com were Hublot watches, Airbus and BA.
The deal with Rolex is part of a year-long partnership between the watchmaker and BBC Worldwide.
As part of the tie-up, Rolex will sponsor all BBC.com content, including news, weather and sport, allowing it to communicate specific brand messages to the roughly 28 million people that reside outside the UK and who use the site.
Kym Niblock, managing director of BBC.com, said the Rolex contract would help to deliver funds to invest in expanding the international reach of BBC.com.
BBC Worldwide has attracted controversy over its policy of carrying advertising on BBC.com, although it is pressing ahead with the plan amid hopes that the organisation will generate millions of pounds in new revenues each year.