A Supreme Court spokeswoman said someone got hold of one of Roberts' credit card account numbers. No further details were given.
However, the Washington Post reports that Roberts told a Starbucks cashier in suburban Maryland that he had to use cash for his morning coffee because he had canceled his credit card after discovering someone had the number.
The last reported criminal incident involving a justice was in May, when someone broke into the Washington home of Justice Stephen Breyer. No one was home at the time.
The Associated Press contributed to this report.