The player is due to meet Sergio Cragnotti on Tuesday evening to discuss personal terms, and sign a five-year contract worth around £3.2 million a year.
According to Italian sources, Valencian director Manuel Llorente along with Cragnotti agreed to the transfer on Tuesday in Formello, Rome.
On Sunday, Mendieta appeared to confirm that his future lay away from the Mestalla and if proven correct, it would appear the Spanish international has got his wish.
All off-season long there has been a battle between the Spanish and Italian press, designed to unsettle the top players of various sides and with Zinedine Zidane moving to Real Madrid, it seemed that it was La Liga sides who had 'won'.
However, the capture of Mendieta by Lazio, gives Serie A a Spanish midfield genius of its own, whilst the possibility of Josepa Guardiola ending up in Italy adds to the spice over which league is 'the best'.
After Real had landed Zidane, it seemed unlikely that Mendieta would move to the Spanish capital, especially after Valencia's new president, Jaime Orti said: "I will never talk to Real about Mendieta. Never."
But after news of the possible transfer reached Real, director of football Jorge Valdano was incensed, saying: "There is nothing to do. Real Madrid won't pay that clause (Mendieta's release clause valued at £44 million) so Mendieta won't come to us.
"It's a sin because the player had already given us a positive answer."
Mendieta will attempt to fill the void left by Pavel Nedved who has moved to Juventus, indeed Lazio, having sold the Czech along with Juan Sebastian Veron to Manchester United, appear to have made room in their midfield for the Spaniard and at the same time reduced their costs, allowing them to make their audacious bid.
