Coburn, who has been in Congress for a total of 15 years, annoounced his decision on Thursday evening.
"I've had a lot of changes in my life," Coburn said in an interview with The Oklahoman, which first reported the news. "This is another one."
Coburn's office confirmed the statement to TPM shortly after.
Coburn's decision means he's ending his time in Congress two years before his term ends.
His decision came a few months after he announced that he would undergo treatment for a recurrence of prostate cancer.
Read Coburn's full statement below:
“Serving as Oklahoma’s senator has been, and continues to be, one of the great privileges and blessings of my life. But, after much prayer and consideration, I have decided that I will leave my Senate seat at the end of this Congress.
“Carolyn and I have been touched by the encouragement we’ve received from people across the state regarding my latest battle against cancer. But this decision isn’t about my health, my prognosis or even my hopes and desires. My commitment to the people of Oklahoma has always been that I would serve no more than two terms. Our founders saw public service and politics as a calling rather than a career. That’s how I saw it when I first ran for office in 1994, and that’s how I still see it today. I believe it’s important to live under the laws I helped write, and even those I fought hard to block.
“As a citizen legislator, I am first and foremost a citizen who cares deeply about the kind of country we leave our children and grandchildren. As I have traveled across Oklahoma and our nation these past nine years, I have yet to meet a parent or grandparent who wouldn’t do anything within their power to secure the future for the next generation. That’s why I initially ran for office in 1994 and re-entered politics in 2004. I’m encouraged there are thousands of Americans with real-world experience and good judgment who feel just like I do. As dysfunctional as Washington is these days, change is still possible when ‘We the People’ get engaged, run for office themselves or make their voices heard. After all, how else could a country doctor from Muskogee with no political experience make it to Washington?
“As a citizen, I am now convinced that I can best serve my own children and grandchildren by shifting my focus elsewhere. In the meantime, I look forward to finishing this year strong. I intend to continue our fight for Oklahoma, and will do everything in my power to force the Senate to re-embrace its heritage of debate, deliberation and consensus as we face our many challenges ahead.
“My God bless you, our state and our country.”