The former Real Madrid forward, who led the Spanish club to five consecutive European Cup triumphs, had suffered a heart attack on Saturday.
The 2014 Champions League winners, who he also managed in two separate spells between 1982-1984 and 1990-1991, published his medical report on their website stating that he was clinically stable but remained in a serious condition.
It has since emerged, however, that he failed to make a recovery.
Di Stefano is considered to be one of the greatest footballers to have ever played the game.
Having also played for River Plate, Millonarios and Espanyol, the Argentine won 23 trophies across a glittering career, winning two European Player of the Year awards in the process.
He also played for three international sides – Argentina, Columbia and Spain - and yet, regrettably, he never featured at a World Cup.