The D.C. case was brought by five individual taxpayers who have all gone without insurance for many years.
The ruling was immediately applauded by the administration.
"We welcome this ruling, which marks the third time a court has reviewed the Affordable Care Act on the merits and upheld it as constitutional," Department of Justice spokeswoman Tracy Schmaler said in a statement. "This court found — as two others have previously — that the minimum-coverage provision of the statute was a reasonable measure for Congress to take in reforming our healthcare system. At the same time, trial courts in additional cases have dismissed numerous challenges to this law on jurisdictional and other grounds. The department will continue to vigorously defend this law in ongoing litigation."