Biden, who has battled health problems over the past year, made the announcement in written statements and a letter to supporters. He declined interview requests and did not schedule a press conference.
"After careful consideration, I have concluded that it is not right to ask for your support in 2014, knowing that my focus would be divided between doing my job as attorney general while at the same time running as a candidate for governor," Biden said in his letter to supporters.
Biden's statement did not indicate whether his decision to skip a third term was affected by his health.
In August, Biden was hospitalized at a Texas cancer center, where he underwent a procedure to remove a "small lesion" from his brain. He mostly has avoided the public eye since, appearing at few public events while working from his Wilmington office, though his doctor said in a February statement that he gave Biden a "clean bill of health."
