After cheers went up from crowds outside the monolithic, downtown court building, which in its lobby boasts a colourful and proud fresco of horse- riding cowboys, a beaming Ms Winfrey emerged to declare: "Free speech not only lives - it rocks!"
The wildly popular Ms Winfrey, 44, was forced to move her entire talk- show operation from Chicago to the Texas panhandle city for the duration of the trial, which generated headlines across the country from the moment it started. Normally soporific and dusty Amarillo, meanwhile, basked in the excitement of famous guests coming into its midst daily for recordings of the Oprah show.
At issue in court was an episode of her programme in April 1996 devoted to mad cow disease in Britain. A guest, Howard Lyman, a rancher-turned- vegetarian, said that while there had been no documented cases of the syndrome in the United States herd, it was bound to strike on this side of the water if it had not already.
Angry Texas ranchers accused Ms Winfrey, her production company and Mr Lyman of defaming beef and falling foul of new and highly controversial "veggie libel" laws. On the books in 14 states in the US, the laws seek to protect foodstuffs from slander or defamation.
Claiming that the offending programme had sent beef prices to a 10-year low, the ranchers were seeking damages from the defendants of almost $11m.
In the course of the show, Ms Winfrey asked Mr Lyman if he believed that an outbreak of "mad cow", or BSE, in the US would make Aids look like the common cold. He concurred that it would, to which Ms Winfrey responded that Mr Lyman had just "stopped me from eating another burger".
But after six hours of deliberation, the Amarillo jury sided with Ms Winfrey's argument that she was merely exercising her rights to free speech. One jury member, Pat Gowdy, said: "We felt that a lot of rights have eroded in this country. Our freedom of speech may be the only one we have left."
The forewoman of the jury, Christy Sams, hinted that finding against the cattlemen may not have been so easy. "We didn't necessarily like what we had to do, but we had to decide for the First Amendment," she said in reference to the US Constitution.
Conceding that the trial had been "very, very difficult" for her personally, Ms Winfrey, none the less, remained defiant in defending her record. During the trial she had the support of friends who came to sit in the court's public gallery, including the black American poet, Maya Angelou.
"I will continue to use my voice," Ms Winfrey declared. "I believed from the beginning this was an attempt to muzzle that voice in this country and I refuse to be muzzled. I will not change the way I operate."
The National Cattlemen's Beef Association, meanwhile, issued a statement saying it was "disappointed" with the verdict.
"In today's world of instant and widespread communications, the impact of misinformation can be devastating on the market for perishable agricultural products," the group said.