HOUSTON — Christopher Hitchens, probably the country’s most famous unbeliever, received the Freethinker of the Year Award at the annual convention of the Atheist Alliance of America here on Saturday. Mr. Hitchens was flattered by the honor, he said a few days beforehand, but also a little abashed. “I think being an atheist is something you are, not something you do,” he explained, adding: “I’m not sure we need to be honored. We don’t need positive reinforcement. On the other hand, we do need to stick up for ourselves, especially in a place like Texas, where they have laws, I think, that if you don’t believe in Jesus Christ you can’t run for sheriff.”

Mr. Hitchens, a prolific essayist and the author of “God Is Not Great: How Religion Poisons Everything,” discovered in June 2010 that he had Stage 4 esophageal cancer. He has lately curtailed his once busy schedule of public appearances, but he made an exception for the Atheist Alliance — or “the Triple A,” as he called it — partly because the occasion coincided almost to the day with his move 30 years ago from his native England to the United States. He was already in Houston, as it happened, because he had come here for treatment at the MD Anderson Cancer Center, where he has turned his 12th-floor room into a temporary library and headquarters.

Mr. Hitchens is gaunt these days, no longer barrel-chested. His voice is softer than it used to be, and for the second time since he began treatment, he has lost most of his hair. Once such an enthusiastic smoker that he would light up in the shower, he gave up cigarettes a couple of years ago. Even more inconceivable to many of his friends, Mr. Hitchens, who used to thrive on whiskey the way a bee thrives on nectar, hasn’t had a drink since July, when a feeding tube was installed in his stomach. “That’s the most depressing aspect,” he said. “The taste is gone. I don’t even want to. It’s incredible what you can get used to.”