(Fortune) -- Pat Woertz, CEO and President of Archer Daniels Midland (Charts), ranks No. 4 on Fortune's 2006 list of 50 Most Powerful Women.

Talk about a brief retirement. In March the 29-year Chevron veteran stepped down from running the $194 billion company's downstream division. By May she had stepped into the corner office at the $37 billion agribusiness giant. Woertz's energy expertise is expected to guide ADM's push in renewable fuels. Her timing was impeccable: Riding a commodities boom, ADM stock has had a good run.

By the key criteria Fortune uses in assembling its annual list - the size, importance, and health of each business in the global economy, and the momentum of each woman's career (along with her social and cultural influence) - there's no question that the power of women in the corporate sphere is rising.

Indeed, it could be called the year of the Most Powerful Woman CEO. The top seven positions on Fortune's 2006 Most Powerful Women list are held by CEOs. They include: Indra Nooyi of PepsiCo (Charts); Anne Mulcahy, Xerox (Charts); Meg Whitman, eBay (Charts); Irene Rosenfeld, Kraft Foods (Charts); Brenda Barnes, Sara Lee (Charts); and Andrea Jung, Avon (Charts).

Next: Full list: 50 Most Powerful Women at http://fortune.com/mostpowerful/

Plus: Most Powerful Women: 10 Highest-Paid at //money.cnn.com/popups/2006/fortune/womenpay/index.html