The Arizona Republican, who will turn 80 in 2016, had previously indicated that this term might be his last. He told supporters at an event in September that he and President Obama would likely complete their terms at the same time.
"The president and I, he's in his last term, I'm probably in mine, the relationship we have had over the past three years is quite good," he said.
McCain later clarified that he had not yet made a final decision.
Ed. Note: This article initially contained a quote attributed to John McCain by Mark Leibovich, where the senator said he was "very much considering" another term. The Washington Post updated their article with audio later Tuesday, which does not contain that quote.