Kerr went from fifth to first in rankings released Monday. She is the first American to be ranked No. 1and fifth woman to win the top spot.
Annika Sorenstam was No. 1 the first 60 weeks of the ranking and Lorena Ochoa occupied the top position for 158 weeks until her retirement this year. Jiyai Shin took over for seven weeks but was passed by Ai Miyazato last week.
Kerr's move in the ratings was fueled by a 19-under-par 269 total last week at the LPGA Championship at Pittsford, N.Y. Her score was 12 strokes better than runner-up Kim Song-hee, the largest margin of victory for the event.
Kerr's rating point average of 10.45 is just better than Miyazato's 10.33. Miyazato finished third at the championship. Shin is ranked third followed by Suzann Pettersen and Yani Tseng. Miyazato, Shin, Pettersen and Tseng were each dropped one spot by Kerr's jump up the chart.
Anna Nordqvist is sixth, the only woman to keep the same place in the Top 10 as last week. Karrie Webb improved one spot to seventh while Kim went from 11th to eighth. Michelle Wie slipped two places to ninth and Angela Stanford fell one to 10th.