Judge Roger Vinson took exception to the law's "individual mandate," which requires Americans to buy health insurance.
He refused to impose an injunction against the law.
Twenty-six states have joined in a challenge against the healthcare law.
Vinson ruled, quote, "because the individual mandate is unconstitutional and not severable, the entire Act must be declared void."
Judge Vinson added, "this has been a difficult decision to reach, and I am aware that it will have indeterminable implications." Judge Vinson was appointed to the bench by President Ronald Reagan in 1983.
The plaintiffs in the case represented more that two-dozen states.
Last month, a federal court judge in Richmond, Virginia, struck down the provision in the law requiring Americans to start buying health insurance in 2014 or pay a penalty, saying it invited an "unbridled exercise of federal police powers."
(Copyright 2011 by VERTEXNews/Newsroom Solutions)