Sanz was a director at Real from 1985 to 1995 before taking over as President, a position which he held until 2000.
He masterminded their European Cup victory in 1998, where they beat Juventus in the final, ending a 32-year drought in the competition they had once dominated.
After lifting La Septima they added another two years later in 2000. He also brought Davor Suker, Roberto Carlos and Nicholas Anelka to the Bernabeu.
Sanz’s son Lorenzo San Duran wrote on Twitter: “My father has just died.
“He did not deserve this end in this manner. One of the best, most courageous and hard working people I have seen in my life. His family and Real Madrid were his passion.”
The triumph in 1998 was Real’s first in Europe’s elite club competition since 1966. He was succeeded as president of Real by Florentino Perez, who ushered in the Galactico era and returned again in 2009.
Sanz purchased Malaga in 2006 before selling the club in 2010.
He was the father-in-law of former Real Madrid defender Michel Salgado, who married Sanz’s daughter Malula.
Sanz’s son Fernando played for Real between 1996 and 1999.