Democrat Maurice Hinchey will leave his job in Washington at the end of the year.
Hinchey will announce on Friday that he will not seek reelection this year.
Hinchey, 73, has completed treatment for colon cancer. His office says he has been declared cancer free by his doctors.
Earlier this month, Hinchey was among 46 House members calling for public disclosure of chemicals used in hydraulic fracturing of natural gas wells drilled on public lands. The Democrat was was first elected to the House in 1992 after 18 years in the New York state Assembly.
Hinchey's website details the wide reach of the 22nd Congressional District: New Yorks' wonderfully scenic 22nd Congressional District includes all or part of eight counties and ranges from the Hudson River, through the Catskills, across the Southern Tier and up to the Finger Lakes. Its cities include Binghamton, Ithaca, Middletown, Kingston, Newburgh and Poughkeepsie.