Marc Faber, editor of the "Gloom, Boom & Doom," has been predicting a major selloff in stocks for the past three years—that is, when he hasn't been calling for global economic collapse or widespread war.

With major stock market averages soaring to record heights in recent weeks, bears have been wrong on most of their bets in 2014. But Faber has remained steadfast, predicting a 20- to 30-percent correction as recently as Monday.

Read MoreMarc Faber predicts 20% to 30% drop in stocks

After being wrong for so long, is the perennial pessimist bound to be right one of these days? Or is Wall Street's patience running thin? During an interview Monday on CNBC's "Halftime Report," Faber defended his record:



"Over my career, somewhere, somehow I must've made some right calls. Otherwise, I wouldn't be in business."



The pessimistic prediction Faber made on Monday was one of his more specific calls. He said stocks would drop 20 to 30 percent by October, after peaking in the next 30 to 60 days.

—By CNBC's Jeff Morganteen.

