Everytown for Gun Safety will mobilize voters to back candidates and ballot issues like enhanced background checks for gun buyers.
The group will look closely at 15 states, including pro-gun states such as Texas, The Associated Press reported.
The former mayor, a billionaire, has made headlines in and out of office for his efforts to curb guns, obesity and smoking.
“If there is a God, when I get to heaven I'm not stopping to be interviewed,” he said. “I am heading straight in. I have earned my place in heaven. It's not even close.”
The National Rifle Association had no immediate comment for the AP, but said it would respond at its annual meeting next week in Indianapolis.
However, the AP did carry a comment from Larry Pratt, executive director of Gun Owners of America, that he made to the New York Times.
"He's got the money to waste,” Pratt said of Bloomberg’s new organization, “So I guess he's free to do so."
-- Bill Miller