Interest rates could be heading significantly higher, the editor and publisher of The Gartman Letter said Monday.

"I think that we've seen a massive top taking place here," Dennis Gartman said. "I think you have to be selling the bond market at the long end of the curve. I think we have a long-term change in the sentiment in the bond market, and I think you have to be a seller of it."

On CNBC's "Fast Money," he said that the nomination of Federal Reserve Vice Chair Janet Yellen to succeed Chairman Ben Bernanke could coincide with the end of a 31-year bull market.

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"I think we will be surprised where rates will be four and five and six years from now," he said. "I think you can see 6 percent yields in the course of the next 10 years without any difficulty, and I think that's the way you have to look at that market."

Within the next two years, yields on Treasury bonds could rise to 4 percent, he said.

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Citing an improving economy, Gartman also said that he was bullish on stocks, copper, shipping and rails.

"I think, actually, outside of New York, things are doing quite well, thank you very much," he said.

—By CNBC's Bruno J. Navarro. Follow him on Twitter @Bruno_J_Navarro.