She shot a 2-over 73 and won the tournament with a three-round total of 5-under-par 208 at Cedar Ridge Country Club.
Paula Creamer, the 19-year-old 2005 LPGA Tour Rookie of the Year, gave Sorenstam all she could handle on Sunday. The American Solheim Cup points leader with 3 1/2 posted a 2-under 69 and finished alone in second place at minus-4.
Maria Hjorth, who was tied for second place with one round to play, struggled to a 4-over 75 and tied for fourth with Diana D'Alessio, who carded a 2-under 69. The duo came in at 2-under-par 211.
France's Karine Icher also played poorly on Sunday. She too shot a 4-over 75 to finish as the last golfer under par at minus-1.
Sorenstam began the final round with a one-shot lead and it was only Creamer that made a move, but it wasn't much of a move on the front nine. Creamer ran home an 8-foot birdie putt at the ninth and that trimmed Sorenstam's lead to four.
Creamer sank a 7-footer for birdie at the 13th and suddenly things were looking more interesting because Sorenstam had to yet to post a birdie. Creamer trailed by three and cut the margin again with a 15-foot birdie putt at the 14th.
Down by two, Creamer missed a 5-foot par putt at the 16th, but that hole proved to be a problem for the leader as well. Sorenstam hit a 4-wood into the right rough at the par-4 hole and she tried to punch an 8-iron under a tree. It did not work as she hit a branch and landed in the rough. Sorenstam's third with an 8-iron came up short of the green, but she chipped inside a foot. Sorenstam tapped in for a bogey and her lead was once again two.
Creamer dropped a shot at the 17th, but kicked in a short birdie putt at the last to remain two down. Sorenstam had two strokes to play with and needed both.
At the 18th, Sorenstam hit her drive left. She knocked a 7-iron over the green and chipped to 6 feet. Sorenstam two-putted from the short distance, but it was enough for the win.
'It wasn't the finish I wanted, but sometimes you just take what you've got,' said Sorenstam, who pocketed $150,000 for the win. 'I was trying to make a few more birdies, but it didn't happen.'
Sorenstam has all but wrapped up the Player of the Year honors and the money title, but the Swede still has goals for the remainder of the 2005 season.
'We still have more tournaments, and I think we've got another six to play in, so the season is far from over for me and for some other players,' said Sorenstam. 'There's a lot of things that are at stake...Vare Trophy.'
Creamer moved to second on the LPGA Tour money list, but couldn't help but feel a little down after missing a chance at her third victory in just her rookie year.
'Obviously I'm a little bummed out after the finish I had on 16, 17 and birdie on 18,' said Creamer. 'It still kind of makes the whole week not as sweet, but I had a chance to win and that's the thing that I always have to look back on.'
Miriam Nagl (68), Jeong Jang (71), Suzann Pettersen (72) and Leta Lindley (73) shared sixth place at even-par 213.
Mi Hyun Kim and Michele Redman each posted matching rounds of even-par 71 on Sunday and tied for 10th place with Shi Hyun Ahn (72) at 1-over-par 214.
Michelle Ellis was tied for second with Hjorth after the second round, but played badly in Sunday's final pairing with Sorenstam. Ellis shot an 8-over 79 and ended in a tie for 13th at plus-2.