Philadelphia police spokeswoman Jillian Russell said Moore was in the hotel's bar with his luggage and guitar when he noticed the guitar was missing. She said it is valued at 20,000 dollars.
Such appeals to the public have helped the band track down stolen gear before. A rental truck full of their one-of-a-kind guitars, amps and drums was stolen in southern California in 1999.
Moore is a founding member of Sonic Youth, an influential alternative band that formed in 1981 in New York City.