George Bush has collided with a police officer during a bike ride on the grounds of the Scottish hotel hosting the G8 summit.
President Bush was going at a "pretty good speed"
The US president suffered scrapes on his hands and arms and was treated by a White House doctor, his spokesman said.
The Scottish police officer, on security duty, was sent to hospital to be treated for a minor ankle injury.
Mr Bush, celebrating his 59th birthday, was said to be going at a "pretty good speed" when he fell from his bike.
It was lightly raining at the time of the accident and Mr Bush slid onto the road, White House spokesman Scott McClellan said.
The doctor bandaged the grazes and Mr Bush was taken back to the summit venue in a van.
It did not prevent him attending a dinner with other leaders of the world's most powerful nations, hosted by the Queen.
Mr Bush took up cycling seriously after a knee injury forced him to give up running some years ago.
This is not the president's first accident.
In May 2004, he was badly grazed after falling off his mountain bike during a ride at his Texas ranch and, in June 2003, he fell off his hi-tech Segway scooter.
In January 2002, he grazed his cheek after choking on a pretzel and fainting.