An aide to Dick Cheney said the former US vice president was in George Washington Hospital after experiencing chest pains.
Mr Cheney's assistant, Peter Long, said in a statement that the 69-year-old was resting comfortably and his doctors were evaluating the situation.
Mr Cheney, who was George W. Bush's vice president, has a history of heart problems and uses a pacemaker.
In 2008, doctors restored a normal rhythm to his heart with an electric shock. It was the second time in less than a year that Cheney had experienced and been treated for an atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart.
Mr Cheney has had four heart attacks, starting when he was 37. He had quadruple bypass surgery and two artery-clearing angioplasties.
The former vice president has kept a high profile since leaving the White House. He sparred with the Obama administration over plans to close the detention facility at Guantanamo Bay, Cuba, and hold the trials of several high profile detainees in civilian courts rather than military tribunals.
Most recently, he made a surprise appearance at the Conservative Political Action Conference, where he accompanied his daughter Liz.
He was greeted with chants of "Run, Dick, Run," but said: "I am not going to do it."
Among his extensive government service, Mr Cheney served as defence secretary under President George H.W. Bush. He supports lifting the ban on gays openly serving in the military, citing a cultural shift in the 17 years since Congress passed the ban.Reuse content