Company: Kraft Foods
Fortune 500 rank: 49
First year as CEO: 2006
Most Powerful Women rank: 1
Rosenfeld made a big show of power this year with her decision to split Kraft into two companies, a reversal of her previous strategy of expanding through acquisitions (like the 2010 purchase of Cadbury). Her new role hasn't been decided but she plans to remain CEO until the deal's expected close in 2012.
NEXT: Patricia Woertz