Bill Fleckenstein is famous for his record as a successful short-seller. Over the past few years, he has been sitting on the sidelines of the market, waiting for a time when it was safe to get short. Now, he says the market looks likely to take a deep dive in the next few months—and that's why he has no regrets about missing out on gains.

"I think the stock market is more crash-prone than ever," Fleckenstein said Tuesday on CNBC's "Futures Now." "So will we get through September and October without some sort of an accident? I don't think we will, but I don't know—we'll just have to see."

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Interestingly, even though the has tripled in price since bottoming out in March 2009, Fleckenstein doesn't wish that he had been investing instead of sitting by and watching.

"If you want to pursue idiots like the Fed doing crazy policies, and if you think you can get out in time, go for it. I don't want to try to do that," he said.

Many of the more bearish market analysts, such as Gina Martin Adams of Wells Fargo, have said that the tailwind of an improving economy is set to overcome the headwind that is the Fed reducing stimulative measures. But Fleckenstein is resolute in his belief that a crash is coming.

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Fleckenstein may have missed out on gains, but "so what?," he asked rhetorically. "When markets decline, how fast it will be taken away from you."

Some traders might regret missing out on what may go down in history books as the bull market of a lifetime, but "I'm not kicking myself," he said. "I don't care, it doesn't matter."

"I don't have to play every day," he added.

—By CNBC's Alex Rosenberg

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