The Atlanta circuit ruling sided with 26 states, including Pennsylvania, that had sued to stop the 2010 law from taking effect. The plaintiffs had argued that the individual-mandate provision requiring people to buy health insurance was unconstitutional.
In a separate case, the Cincinnati-based Sixth Circuit appeals court upheld the individual mandate in June. And earlier this month, a three-judge panel of the Fourth Circuit appeals court in Richmond, Va., rejected two lawsuits on technical grounds.
The Atlanta ruling was made in August by a divided three-judge panel of the 11th Circuit appeals court. It concluded that Congress had overstepped its authority when lawmakers passed the individual-mandate provision.
The administration could have asked the full 11th Circuit court to hear the case, potentially delaying review by the Supreme Court.
A fourth appeals court to deal with a lawsuit over the health-care law, the U.S. Circuit Court of Appeals for the District of Columbia, heard oral arguments Friday but has yet to rule.
The Supreme Court is widely expected to have the final say on the law, especially now that appeals courts have disagreed on it and one has struck down a key provision. The real question has been timing, which has political as well as legal ramifications.
To hear and decide the case by late June, when the court wraps up its forthcoming term, the justices would have to act by January to accept and schedule an appeal.
It typically takes a couple of months or more from the time an appeal is filed at the court until the justices decide whether to hear it.
In arguments leading up to the Atlanta appeals panel ruling, the Obama administration said that Congress had used a "quintessential" power - its constitutional ability to regulate interstate commerce, including the health-care industry - when it passed the overhaul law.
Administration officials said at the time that they were confident the 11th Circuit ruling would not stand.
