Dempsey, 61, a graduate of West Point Military Academy, was appointed in October 2011 after serving as the US Army chief.
Obama also re-nominated Admiral Sandy Winnefeld as the Vice Chairman of the Joint Chiefs of Staff today.
"These two superb officers have led our military and their families with great distinction, deep conviction, and absolute integrity over the past two years and I am confident in saying that our nation is safer and more secure today because of their visionary, dedicated, and tireless leadership," Obama said in a statement.
"During what are challenging times, this is the right team for the job" said Hagel at the Pentagon, while the nominations are subject to approval of the Senate.
Both Dempsey and Winnefeld began their two year terms in 2011.
