Goals by David Silva, Jordi Alba, Fernando Torres and Juan Mata brought the world champions to an easy victory and a record third win in major tournaments after the 2008 Euro championship and the 2010 World Cup.
Injury forced four-times world champion Italy to end the game with ten players.
Spain took the lead in the 14th minute and though Italy responded with eight goal attempts, the team, which was without star striker Mario Balotelli, was thrashed with Spain's captain Iker Casillas keeping his record of not conceding a goal in a tournament knockout stage since the 2006 World Cup.
Italian fans who had defied the heat and gathered in piazzas in all major cities to watch the game were deluded after hopes had been raised by Italy's 2-1 win over Germany in the semi-finals against all expectations.
In the capital Rome, some 500,000 fans gathered at the Circo Massimo and in Milan's Piazza del Duomo many of the 60,000 fans who had chosen to watch the game outdoors left midway through the match. Almost all T-shirts written with 'European Champions' on sale across Italy for 15 euros remained unsold.
Italian Prime Minister Mario Monti who watched the Euro final in Kiev praised the team after the game: 'I went into the changing room and told the boys that they made us dream. Tonight we have woken up, but we must be proud of them'.