The Catalans have had their troubles in recent weeks, but they have now clinched a fourth league title in five years
Jose Mourinho's side went into the clash at Cornella-El Prat knowing that they had to win to prolong their rivals' title celebrations but could only muster a 1-1 draw, with Gonzalo Higuain cancelling out Christian Stuani's opener.
The title success is the 22nd in the Catalan giants' 113-year history and their fourth in the last five seasons after relinquishing their grip on the championship to Real Madrid last term.
Ahead of the Vicente Calderon to face Atletico Madrid on Sunday, Barca have 88 points, 12 short of equalling Madrid's record tally of 100, which they set last year.
Los Blancos, meanwhile, have 81 and just two games to spare, meaning they cannot overhaul the Liga leaders.
Club president Sandro Rosell wrote on Twitter: "It's very special, the reward for the effort, the spirit and perseverance of a remarkable group of people."
Tito Vilanova's troops have netted 105 goals after 34 games, 20 short of the best-ever total and have lost just two games, against Real Sociedad and Real Madrid.
They are unbeaten on home soil this term in La Liga, but were eliminated from the Copa del Rey by Madrid and the Champions League by Bayern Munich.
Barca and Atleti meet at 19:00CET on Sunday.