The union said most of its 10,000 eligible members participated in the vote, with the contract ratified by a 2-1 margin, the Chicago Tribune reported. Union officials said the four-year pact improves pay, benefits and work rules.
The contract is the first since United merged with Continental in 2010.
"The era of bankruptcy and concessionary contracts is now over," union leaders said in a statement. "For too long, the pilots of United and Continental have had to shoulder more than their share of the burden as our respective airlines struggled through the difficult economic times of the past decade. We now stand ready to embark on a fresh start for the pilots and the airline."
Fred Abbott, a United senior vice president for flight operations, called the contract "an important step forward" for both sides.
Pilots have been working without a contract and had taken a preliminary strike vote. The union and company agreed to a preliminary deal with a mediator in August but then spent several months working out the details.