(Adds biographical details)
Jan 16 (Reuters) - U.S. Senator Tom Coburn, a Republican from Oklahoma, said on Thursday that he would leave Congress at the end of this year.
Coburn, 65, said in a statement that although he is battling cancer, that was not the reason he decided to resign. His departure will leave two years left in his term.
"This decision isn't about my health, my prognosis or even my hopes and desires," Coburn said in the statement, which was posted on his website.
"As a citizen, I am now convinced that I can best serve my own children and grandchildren by shifting my focus elsewhere," he said. "In the meantime, I look forward to finishing this year strong."
Coburn's departure is not likely to alter the political calculus of the Senate, since he comes from a solidly Republican state.
Staunchly pro-life, Coburn has also fought hard to eliminate what he viewed as waste in government, according to his biography.
The biography says Coburn has offered "more amendments than any of his colleagues," including one opposing the so-called Bridge to Nowhere in Alaska, and another against funding for a museum commemorating the 1960s Woodstock music festival in New York state.
Coburn was one of several Republicans who sharply criticized efforts by the GOP's Tea Party wing to shutdown the government last fall as a way to demand that the Affordable Care Act, commonly known as Obamacare, be de-funded.
A physician who says he has delivered 4,000 babies, Coburn was first elected to Congress in 1994, and served three terms, according to a biography posted on his website.
He left after his third term, but then ran for Senate in 2004, the biography said. His website says he is a three-time cancer survivor. He is a ranking member of the Homeland Security and Governmental Affairs Committee. (Reporting by Sharon Bernstein; Editing by Lisa Shumaker and Ken Wills)