The Congressional Budget Office estimates that about 32 million previously uninsured people will gain coverage by 2016, when health care reforms are fully implemented. But will these newly insured people use the health care system in the same ways as others? Is insurance enough to change patterns of use? The example of Medicare may provide some insight. This Issue Brief summarizes research that investigates how health care use and patterns change among the uninsured and insured once they gain Medicare coverage at age 65.