Dettori, 54, who has won hundreds of races all over the world and continues to ride, said in a statement: "For the last six months, my advisers have been working with HMRC in an attempt to find a solution to my financial situation.
"Regretfully, I will be filing for bankruptcy.
"I am saddened and embarrassed, and would advise others to take a stronger rein over their financial matters."
He said the consequences of bankruptcy "will affect me for many years".
Last year, Dettori was revealed by the Upper Tribunal court to be involved in a dispute with HMRC over a scheme, devised by specialist advisers, to reduce income tax payments.
The riding legend had sought anonymity during the proceedings but this was lifted following applications to the court by HMRC and the media.
Dettori left the European stage with a flourish, winning the Champion Stakes at Ascot, Britain's most valuable race, aboard King of Steel in October 2023.
He was also one of very few riders to enjoy a high profile with the general pub...