Following several security breaches at the World Trade Center site, the Port Authority is handing security responsibilities over to the same company that guards the airports.
Allied Barton provides unarmed guards.
Its contract will be increased by about $60 million.
Summit Security Services, which had been doing the job at the World Trade Center, will continue to provide security at other Port Authority facilities.
Three BASE jumpers leaped from the top of 1 World Trade Center last fall, and in March, a New Jersey teenager climbed to the top of the tower's spire.