The mayor began his weekly WOR Radio show Friday by saying: "Let's start with the most important thing this weekend. Go Giants!"
The San Francisco 49ers are hosting the Giants in the NFC Championship Game Sunday.
Bloomberg said he was wearing a blue tie and a blue shirt.
He said he'd also be sure to mention Big Blue while speaking later Friday at the U.S. Conference of Mayors in Washington.
He said if the Giants should go on to the Super Bowl, he's sure he and New Jersey Gov. Chris Christie could work out something about where to hold the celebration. The New York team plays in New Jersey.