The trophy was Barca's to lose as they started the day with a one point lead over Real and the head-to-head advantage in their favour, and they held their nerve in front of a packed and expectant Nou Camp.
Valladolid's Luis Prieto scored an own goal after 27 minutes and soon after Pedro doubled the lead before Argentine World Player of the Year Lionel Messi wrapped up the victory with his 33rd and 34th league goals of the season in the second half.
Any hopes Real had had of sneaking the title on the last day of the season disappeared when they were held to a 1-1 draw at Malaga.
Barca finished the season with coach Pep Guardiola's seventh trophy in two years and a Spanish league record of 99 points.
Real pushed Barca all the way and finished three points back in second, but empty handed despite having spent around 250 million euros ($317.6 million) on new players in an attempt to wrest the initiative from their arch-rivals.
"I have huge admiration for what Real Madrid have achieved. They weren't champions only because the other team were just a little bit better," Guardiola told a news conference.
"We only lost one game all season, and this is down to the excellent, hard-working and humble group of players we have," he added.
Malaga's draw saved them from them from drop but Valladolid were sent down to the second division along with Tenerife who lost 1-0 at Valencia, and Xerez who drew 1-1 at Osasuna.
INCREDIBLY NERVOUS
Barca started incredibly nervously and a last-ditch block from Carles Puyol prevented Valladolid's Manucho from scoring a shock early goal.
They struggled to settle, missing the calming influence of suspended playmaker Xavi, until cheers spread round the Nou Camp after nine minutes as news filtered through that Malaga's Duda had netted against Real.
Pedro cut to the byeline and crossed low to the near post and without a Barca player near him Prieto deflected the ball past his own keeper and the hosts were on their way.
A busy Messi set up the second soon after, spreading the ball to his right for Pedro to nutmeg Jacobo in the one-on-one.
Van der Vaart finally found a way past inspired Malaga goalkeeper Gustavo Munua to level at the Rosaleda just after the re-start, but it soon became irrelevant.
Back at the Nou Camp, Yaya Toure powered to the byeline in the 62nd minute to cross, Pedro dummied, and Messi tapped in the third kicking off the celebrations around the stadium.
Messi delighted the home fans by running through to score a solo effort in the 76th, but the festive atmosphere was not completed until the chants for Andres Iniesta to be given a run out were answered five minutes from time.
The Spanish international, and crowd favourite, came on as a substitute after over a month out injured to a huge roar and all the players crowded together in a huddle to enjoy their victory with the fans at the end.
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