George Pataki, the governor of New York state, is expected to announce Wednesday that he will not seek a fourth term next year.
Associates say that Mr. Pataki, who is considering a possible run for president in 2008, told a group of supporters and aides of his decision Tuesday night.
People who attended the meeting say the governor did not say whether he would launch a bid for the Republican Party presidential nomination.
Mr. Pataki took office nearly 11 years ago after defeating Democrat Mario Cuomo. Polls now show Mr. Pataki trailing New York state Attorney General Eliot Spitzer, the Democrat who hopes to succeed him as governor.
Mr. Pataki is known as a moderate who supported liberal causes such as abortion rights as well as tough-on-crime conservatism.