A statement e-mailed to The Associated Press from spokeswoman Liz Rosenberg says the couple has agreed to divorce, and asks the media to respect their privacy.
The statement, co-signed by Ritchie's representative, says the couple had not agreed to a settlement.
The months-old rumor of an imminent announcement heralding a divorce resurfaced, CBS News correspondent Richard Roth reports from London.
Wednesday morning it came from Britain's biggest daily newspaper, The Sun, which has a reputation for surprisingly accurate scoops - sometimes.
"I think in the last three weeks in particular they've had so many arguments that it's just come to the stage where they've decided to finish with the pretense," said Gordon Smart, The Sun's show business editor. "I think there will be an announcement imminently about their marriage being over."
But the celebrity circuit has been abuzz for months that the couple is no longer getting along.
Madonna and Ritchie have three children, several huge houses, hundreds of millions in assets and, reportedly, high-priced attorneys have already been hired.