The 21-year-old is due to arrive at White Hart Lane later this week with a view to completing an estimated £10.5m deal from Internacional.
Sandro will not join the club, however, until the conclusion of the Copa Libertadores in August, while a work permit must also be granted.
Sandro is a defensive midfielder who has made 73 appearances for Inter, scoring three times, and made his full debut for Brazil in a World Cup qualifier with Chile.
Spurs boss Harry Redknapp is delighted with his new acquisition.
“He is an outstanding young player,” he said. “He is on the verge of the Brazilian team, he has already played for Brazil and captained the Under-18s, 19s and 21s. He is strong. He looks a very, very good player so I am looking forward to getting him here.”
Sandro’s arrival casts further doubt on the future of Wilson Palacios, who has admitted he is using Spurs as a “stepping stone” for a dream move to Real Madrid.