The 74-year-old football great had to cancel a book-signing at a museum named for him in his native city of Santos after complaining about his stomach on Wednesday.
"He made some tests and will be discharged tomorrow. Everything is fine," Jose Fornos Rodrigues, the former player's personal aide, said.
A spokesman for the hospital told Reuters that Pele was admitted Wednesday evening but did not say when he would be allowed to leave the facility.
Pele, widely regarded as the best footballer of all time, helped Brazil win the World Cup three times.
He was named "Football Player of the Century" by the world football body FIFA, "Athlete of the Century" by the International Olympic Committee and a "national treasure" by Brazil's government.
(Reporting by Alonso Soto; Editing by Alan Crosby and Ken Wills)
