But is the number real? Is it overstated, or even understated?
FactCheck.org's Jess Henig took a look at the data, and comes to the conclusion that it may not be as high as that, but because of the job losses over the past months the number is likely to increase.
•The Census Bureau estimates that 45.7 million lacked health insurance at any given time in 2007. But fewer lacked coverage for the full year, and more did without for one or more months during the year. All three numbers are likely to be higher for 2008 due to massive job losses.
•Twenty-six percent of the uninsured are eligible for some form of public coverage but do not make use of it, according to The National Institute for Health Care Management Foundation. This is sometimes, but not always, a matter of choice.
•Twenty-one percent of the uninsured are immigrants, according to the Kaiser Family Foundation. But that figure includes both those who are here legally and those who are not. The number of illegal immigrants who are included in the official statistics is unknown.
•Twenty percent of the uninsured have family incomes of greater than $75,000 per year, according to the Census Bureau. But this does not necessarily mean they have access to insurance. Even higher-income jobs don't always offer employer-sponsored insurance, and not everyone who wants private insurance is able to get it.
•Forty percent of the uninsured are young, according to KFF. But speculation that they pass up insurance because of their good health is unjustified. KFF reports that many young people lack insurance because it's not available to them, and people who turn down available insurance tend to be in worse health, not better, according to the Institute of Medicine.