Sorenstam completed the victory at 21-under-par 195 at Seta Golf Course. She became the first player in PGA or LPGA Tour history to win the same event five consecutive years.
The Swede, who had won this crown by nine strokes each of the last two years, claimed her 65th career title on the LPGA Tour.
Jenny Rosales closed with a 6-under 66 to end alone in second place at 18- under-par 198.
Yuri Fudoh matched Sorenstam's 64 in the final round to climb into a tie for third place at 16-under-par 200. She was joined there by first- and second-round leader Young Kim (70) and Sophie Gustafson (66).
Kim led by one entering the round and a birdie on the second gave the Korean a two-stroke cushion. However, she bogeyed the fourth to slide back to 14 under.
Gustafson birdied four of five holes from the third to jump to minus-14 and a share of the lead with Kim.
Sorenstam had been biding her time, as she opened with five straight pars. She then eagled the par-5 sixth. Over the three-day event, Sorenstam played the hole at 4 under par.
The eagle got Sorenstam to 15 under and a share of the lead with Rosales and Kim. The Korean birdied the sixth, while Rosales also eagled the par-5 to get to minus-15.
The 34-year-old Sorenstam took the outright lead for the first time in the final round with a birdie on the par-four eighth. Rosales joined her at 16 under as she birdied No. 10.
Sorenstam again moved one ahead as she sank a birdie try on the 11th. Rosales, playing alongside Sorenstam and Kim, birdied 12 to forge another tie. Kim, who birdied the 11th, also birdied 13 to create a three-way tie at 17 under.
From there, it was all Sorenstam. She birdied the 14th for the third straight round to move to 18 under. The Swede made it two in a row as her birdie putt at the 15th fell into the cup.
Sorenstam poured in back-to-back birdies from the 17th to close out the win in style. She has posted a cumulative total of 95 under par in her five straight wins here.
With 17 and 18 both par-5s, Rosales had an outside chance to force a playoff. However, she could only manage a birdie on the 17th and a par at the last to finish three back.
Meena Lee, who won the Canadian Women's Open earlier this year, carded a 6- under 66 on Sunday to end at 14-under-par 202. She was joined there by Karine Icher (67) and Women's British Open champion Jeong Jang (69). Karrie Webb finished alone in ninth at 12-under-par 204 after a final-round 71.