Nate McLouth hit his fourth home run of the season and Freddy Sanchez had two hits and an RBI for the Pirates, who have lost three in a row and nine of 11.
For the second straight game, Philadelphia jumped out to a 6-0 lead against Pittsburgh.
The Phillies scored five runs in the first and sent 10 batters to the plate against starter Matt Morris, who needed 49 pitches to get out of the inning.
Morris (0-4) retired the first two hitters he faced, but the next seven reached base safely. Utley started things off with a single to right field and Howard followed with his fifth home run of the season to deep center to give Philadelphia a 2-0 lead.
Howard had been relegated to pinch-hitting duties the past two games as he works his way out of an offensive slump. He finished 1-for-4 with a walk and two strike outs, and is hitting .178 with 37 strike outs in 90 at-bats this season.
Eric Bruntlett added a run-scoring single in the first, and two errors by Pittsburgh led to the other two runs.
Philadelphia made it 6-0 in the second when Jenkins' two-out single scored Utley, ending Morris' night.
Morris pitched 1 2-3 innings and allowed six runs and six hits. He walked one hitter and struck out one, raising his ERA to 9.67 in five starts this season.
Kendrick (2-2) allowed four runs and seven hits before being removed after allowing McLouth's home run and a single to Sanchez to lead off the eighth. He walked none and struck out two and won for the first time since his first start of the season April 4 against Cincinnati.
McLouth, who had a 19-game hitting streak stopped Tuesday, broke out of an 0-for-15 slump with an RBI single in the third. He finished 2-for-4 with two RBIs.
Notes: Howard's homer was the first of his career against Pittsburgh. He's now homered against every major league team he's faced. ... Utley went 2-for-4 with a walk and has hit safely in 10 of his last 11 games. ... Pittsburgh's Xavier Nady doubled in the fourth and has now hit in 14 straight games.
