Alexis Sanchez opened the scoring with his first goal of the season after less than six minutes and Lionel Messi celebrated putting pen to paper on his two-year contract extension earlier this week by notching one - for the 13th straight game in La Liga - on 13 minutes.
David Villa's neat finish made it 3-0 in the 57th minute and substitute Cristian Tello added another 11 minutes from time. Getafe substitute Alvaro Vazquez then grabbed a consolation for the visitors but there was still time for Andres Iniesta and Gerard Pique to add further gloss to the scoreline for the hosts.
The result lifted Barca 12 points clear of Atletico Madrid, who fell to a shock 2-1 defeat to Rayo Vallecano later in the evening, and restored the leaders' 16-point advantage over third-placed champions Real Madrid.
Barca, still under the guidance of assistant coach Jordi Roura with head coach Tito Vilanova undergoing cancer treatment in New York, freshened up their line-up following the international break - making six changes from last weekend's 1-1 draw at Valencia.
Adriano, Carles Puyol, Thiago Alcantara, Alex Song, Alexis and Villa came in for Dani Alves, Javier Mascherano, Xavi, Sergio Busquets, Cesc Fabregas and Pedro Rodriguez.
Getafe were without goalkeeper Miguel Angel Moya following his red card in last weekend's 3-1 win over Deportivo La Coruna, with defenders Rafa (suspended) and Juan Valera (back problem) also out.
Several members of the Catalan club's squad clocked up considerable air miles this week in attending Spain's midweek friendly against Uruguay in Qatar.
But Barca showed no signs of tiredness, despite the unfamiliar kick-off time, and forged ahead with less than six minutes on the clock.
Iniesta's brilliant ball took out three defenders and found Alexis, who had eluded the Getafe centre-backs. He produced a tidy first touch and then kept his cool to slot a left-footed shot past advancing goalkeeper Jordi Codina.
Just seven minutes later it was 2-0 courtesy of Messi's 299th goal for Barca - his 35th in the league this season.
Again Iniesta was at the heart of the move. The Spain midfielder provided the perfect pass for Thiago, who unselfishly laid the ball off for Messi to stab home from eight yards with his deadly left foot.
That left foot should have made it 3-0 on the half-hour when it connected with Alexis' superb cross from the right. The Argentina forward's effort had Codina beaten but struck the right post.
Two minutes later Villa prodded a first-time shot narrowly wide from 12 yards following Jordi Alba's low early ball from the left.
Messi too had another sight of goal before the interval but had to stretch to reach Villa's chip from the left and could only direct his header over the bar.
Adriano picked up a knock and had to be replaced by Dani Alves at half-time, but the change did not disrupt Barca's rhythm.
The hosts almost scrambled in a third goal in the 57th minute but Codina and Getafe defender Alexis combined to deny Messi and Alexis Sanchez.
Less than 60 seconds later it was 3-0, though, and it was another delightful Barca move.
Messi and Iniesta were inevitably involved in the build-up, feeding the ball out to Alba on the left. The Spain full-back threaded a measured ball through for Villa to calmly direct his left-footed shot through Codina's legs from the corner of the six-yard box.
Alexis Sanchez made way for Tello in the 73rd minute, and the 21-year-old substitute needed less than six minutes to get his name on the scoresheet.
Messi surged forward looking for his 300th Barca goal but found no way through so turned to his right and set up Tello, who placed his right-footed shot confidently past Codina from the edge of the box.
Getafe substitute Vazquez capitalised on sloppy defending from Alba to poke home a consolation for the visitors seven minutes from time, but it mattered little as Barca struck twice more in the closing stages to seal the rout.
First Iniesta got the goal his industry deserved when another Messi burst ended with the ball breaking fortuitously for him to fire home, and then Thiago broke the offside trap and selflessly teed up a simple tap-in for Pique.