Sandro has appeared on 73 occasions for Inter, scoring three times, and he helped them to a second-place finish in Campeonato Brasileiro Série A last season to qualify for the 2010 Copa Libertadores.
The highly-rated player made his international debut against Chile in a World Cup 2010 qualifier last September.
He has also been capped on eight occasions for the national team's U20 side and was their captain as they triumphed in the South American Youth Championship in Venezuela in Feb 2009.
Harry Redknapp, the Tottenham manager, said: 'He is an outstanding young player. He is the verge of the Brazilian team, he has already played for Brazil and captained the U18s, 19s and 21s.
"He is strong and he looks a very, very good player so I am looking forward to getting him here.'