Crisis-hit Parma, who are in administration, said in a statement they had accepted a proposal from Sanz's company to take 100 percent ownership of the Serie A club.
The statement said they expected the exchange of property ownership to be fully completed by September 20.
Sanz was president of Real from 1995 to 2000 and was at the helm when Real won the European Cup in 1998 and 2000. His arrival will bring hope that Parma could return to the Serie A elite.
The club have been in search of new owners since a financial scandal hit their former backers, dairy company Parmalat.
Last season the twice UEFA Cup winners only ensured top flight survival via a relegation play-off win over Bologna.
The close season saw further uncertainty as Parma's top player, Italy striker Alberto Gilardino, was sold to AC Milan while a takeover bid from a Swiss businessman fell through.
This week, Parma brought in former Lazio striker Bernardo Corradi on loan from Spanish club Valencia and, after Sanz's takeover, more arrivals from Spain could be likely.
The Spaniard made his money as a property speculator and took over the Real Madrid presidency from Ramon Mendoza in 1995. He was dealt a shock defeat by Florentino Perez in the presidential election in 2000 just months after Real had won a second European Cup in three seasons.
Perez claimed Sanz had led Real to the brink of economic disaster by running up a debt of close to $250 million.
In last year's elections Sanz said Real had lost their traditional values of humility and hard work and the club and players had become increasingly arrogant.
He also said he has reached agreements to sign Czech Republic internationals Milan Baros and Tomas Rosicky as well as Portugal midfielder Maniche.
But Perez won a landslide victory, polling over 94 percent of the votes cast, while Sanz polled just over four percent.
Sanz was subsequently linked with a possible takeover of bankrupt Swiss side Servette, but nothing came of it.
His daughter is married to Real Madrid right back Michel Salgado.