According to Spanish media, Sanz, 76, had been in intensive care.
Sanz, Real Madrid’s president from 1995 to 2000, had also suffered from renal disorder and diabetes.
Real Madrid conveyed condolences to his family and friends in a statement on their official website.
“Real Madrid C. F., the club president and Board of Directors all wish to express the deepest regret at the passing of Lorenzo Sanz, who was club president of Real Madrid from 1995 to 2000.
“The club wishes to convey its condolences to his wife Mari Luz, his children, Lorenzo, Francisco, Fernando, María Luz (Malula) and Diana, as well as his family and friends. Our condolences are shared by all madridistas,” said the statement.
It is also touted the club’s success under his leadership:
“During the presidency of Lorenzo Sanz, Real Madrid continued to add to its history and legendary status. He was president of the club when, after 32 years, the club won its much awaited seventh European Cup, in Amsterdam in 1998.
“With Lorenzo Sanz as president of Real Madrid, the club won two European Cups and an Intercontinental Cup, a league title, a Spanish Super Cup, a basketball league title and the Saporta Cup.
“Today, all of madridismo is in mourning following the passing of the president who dedicated a huge part of his life to his great passion: Real Madrid.
“Given the current circumstances, Real Madrid will give him the recognition he deserves as soon as possible.”
