"No one knows how to do more with less than yours truly," said Robert Burck, who has become a feature of the Times Square area.
"And that's the kind of thinking I plan on sharing with my fellow New Yorkers when you elect me."
The long-haired, tattooed Burck said on his website that he plans to make an official announcement at his regular haunt on Wednesday.
Dressed in nothing more than a cowboy hat, boots, and a pair of white underpants emblazoned with the words Naked Cowboy, Burck earns about $1,000 (£600) a day busking.
He aims to run against Mayor Michael Bloomberg, a billionaire and Wall Street whiz hoping for a third four-year term.
Mr Bloomberg has already spent millions of dollars on his campaign, including on a blizzard of television commercials.
His only real challenger, the little-known city figure William Thompson, has so far struggled to be heard.
