Pele is “stable” after being admitted to hospital for the second time in a month.
The 74-year-old, who won three World Cups with Brazil, underwent surgery for kidney stones on 13 November.
Now he has been readmitted with what local media say is a urinary infection.
A spokesman for Albert Einstein Hospital in Sao Paulo said he was undergoing “medical evaluation” and was “stable”.
Pele was previously accompanied to the same hospital by aide Jose Fornos Rodrigues.
Pele is widely regarded as the greatest footballer of all time
He was kept under observation for two days, meaning he missed a book launch in his hometown of Santos.
Born Edson Arantes do Nascimento, the man the world knows as Pele is regarded by many as the greatest footballer of all time.
In 1999 he was named Athlete of the Century by the International Olympic Committee.
His return for further treatment comes on the day his son, born Edson Cholbi do Nascimento but known as Edinho, was released from jail in Brazil to appeal a money-laundering conviction.