Where did the most powerful women go to B-school?

For Fortune's Most Powerful Women, the MBA degree is clearly the degree of choice. Some 18 out of 50 women have them. All told, members of this year's list are a highly educated bunch. Thirty-nine out of the 50 women on the list have advanced degrees, which includes three lawyers. Xerox's Ursula Burns has a master's in mechanical engineering from Columbia, and Walt Disney's Anne Sweeney has a master's in education from Harvard.

Harvard Business School leads the pack with five of Fortune's most powerful women, from newly installed Hewlett-Packard CEO Meg Whitman to Facebook chief operating officer Sheryl Sandberg

The alumni and their rankings on our list are:

• Meg Whitman, Hewlett-Packard: No. 9
• Sheryl Sandberg, Facebook: No. 12
• Abigail Johnson, Fidelity Investments: No. 18
• Mary Callahan Erdoes, JPMorgan Asset Management: No. 24
• Lynn Elsenhans, Sunoco: No. 35

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