One million journeys have been made on cycles in London's bike hire scheme since its launch 10 weeks ago.
More than 90,000 people have signed up as members of the £140m scheme since it began on 30 July.
It had been hit by some technical problems at the beginning and a charity has called for helmets to be part of the hire.
But mayor Boris Johnson, who has said only three bikes had been stolen, said its success had "gladdened my heart".
"A million 'thank yous' go to Londoners for the warmth with which they have embraced our beautiful blue bikes," he said.
"The zest in which people have taken to two wheels and joined the cycling revolution we are engendering in the capital has gladdened my heart."