Christie, 49, has said for months that he would not seek the Republican nomination to run against President Barack Obama next year, saying he is not ready.
Heavy pressure from donors and party activists prompted the rising star in the Republican Party to reconsider. He discussed the issue with top advisers and his wife for days.
A Republican source, who spoke on condition of anonymity, said Christie had telephoned potential donors to tell them he had decided not to run.
He scheduled a 1 p.m. (1700 GMT) news conference in Trenton to announce his decision.
Christie would have faced the challenge of organizing a national campaign and building a fund-raising network in short order.
The first US nominating contests, the Iowa caucuses and the New Hampshire primary, are about three months away. The deadline for filing a formal candidacy in the early states is rapidly approaching.
Christie’s decision could benefit former Massachusetts Governor Mitt Romney because the two would have been competing for the same middle-of-the-road establishment Republicans.
Many activists had wanted Christie to run because he is an electrifying presence and has a strong fiscal record in New Jersey.
