Annika Sorenstam, who has not won on the LPGA Tour since the MasterCard Classic in early March, remained in first, followed by Ochoa, who collected her second win this season at the rain-shortened Sybase Classic.
Paula Creamer, Karrie Webb and Cristie Kerr rounded out the top-five for the second week in a row.
Yuri Fudoh, Juli Inkster, Ai Miyazato, Hee-Won Han, who tied for second at the Sybase Classic, and Women's British Open champion Jeong Jang occupied spots 6-10.
Shiho Ohyama, Brittany Lang, Natalie Gulbis, Mi Hyun Kim and Pat Hurst stayed in their places from last week.
Ji-Hee Lee climbed three places to No. 16 this week. Jee Young Lee, Sakura Yokomine and Meena Lee all dropped one spot to accommodate Ji-Hee Lee's ascension.
Akiko Fukushima held on to the 20th ranking.