Sunday's London Marathon set a world record for the number of finishers, eclipsing the previous mark of 55,646 in New York last year, organisers said.
A total of 56,640 runners crossed the finish line, Guinness World Records announced on Monday.
Kenyan Sabastian Sawe won the men's elite race while Ethiopian Tigst Assefa shattered the women's-only world record.
"We are thrilled to have broken the Guinness World Records title," Hugh Brasher, CEO of London Marathon Events, said in a statement on Monday.
"It was a fantastic occasion to see 56,640 people cross the iconic finish line on The Mall throughout Marathon day. We hope the thousands of people watching yesterday were inspired to register in the 2026 TCS London Marathon Ballot."
The London Marathon was already the most popular in terms of ballot entries, with 840,318 people applying for the 2025 race.
It is also the world's largest annual one-day fundraising event with more than £1.3 billion pounds ($1.73bn) raised for charity since 1981.