Joanna Dennehy, 30, of Peterborough, has been charged with the three murders in Cambridgeshire, the Crown Prosecution Service said.
Kevin Lee, 48, was found in a ditch in Newborough on March 30. He died from stab wounds to the chest.
Lukasz Slaboszewski, 31, was stabbed in the heart. John Chapman, 56, was stabbed in the neck and chest. They were found at Thorney Dyke on April 3, the BBC reported.
Grace Ononiwu, the chief crown prosecutor for the east of England, said Dennehy would appear at Peterborough Magistrates' Court at a later date.
While Leslie Layton, 36, has been charged with perverting the course of justice, Robert Moore, 55, has also been charged with assisting an offender in connection with the case.