In 2005, Dr. David Himmelstein and Warren published a study on bankruptcy and medical bills, which claimed that half of all families filing for bankruptcy did so in the aftermath of a serious medical problem. The finding was particularly noteworthy because 75% of those who fit that description had medical insurance. This study was widely cited, although critics from the insurance industry argued that the criteria used were too loose.. In 2007, the team repeated the study, using more robust criteria. They concluded that the proportion of medical bankruptcies had increased to 62% of personal bankruptcies and that, once again, about three-quarters of those families had health insurance at the onset of their medical problems.

On November 14, 2008, Ms. Warren was appointed by United States Senate Majority Leader Harry Reid to chair the five-member Congressional Oversight Panel created to oversee the implementation of the Emergency Economic Stabilization Act. The Panel releases monthly oversight reports that evaluate the government bailout and related programs.

The Panel's monthly reports have covered foreclosure mitigation, consumer and small business lending, commercial real estate, AIG, bank stress tests, the impact of TARP on the financial markets, government guarantees, the automotive industry, and many other topics. The Panel has also released special reports on financial regulatory reform and farm loans. For each report, Warren releases a video on the Congressional Oversight Panel's website explaining key findings. All reports and videos are available at cop.senate.gov.

In her role as Chair of the Panel, Warren has testified many times before House and Senate committees on financial issues.

In an interview at Newsweek, December 7, 2009 entitled "Reining in, and Reigning Over, Wall Street" Elizabeth Warren was asked: "Congress is trying to reform financial regulation, and it can get a little abstract. Where should people focus?"

She responded:

While not officially on the short list of potential nominees to replace retiring US Supreme Court Justice John Paul Stevens , members of the media have speculated on her potential service on the court. In an interview by Tavis Smiley, Warren was asked about serving on the Court and also about heading a potential Consumer Financial Protection Bureau. She was complimented by Tavis on her diplomatic answers and she asserted that she has not been asked to serve in either of those capacities. The Wall Street Journal has reported that Warren is the top pick of Democratic leaders in Congress to head the new consumer agency. There have also been calls for her to challenge Senator Scott Brown in Massachusetts in the 2012 election.

Warren was named one of Time Magazine's 100 Most Influential People in the World in 2009 and 2010.

In December 2009, the Boston Globe named Warren the Bostonian of the Year.