A tearful Christine Beatty offered the guilty pleas to a pair of felony obstruction of justice counts Monday morning in a Detroit courtroom.
Under a deal with prosecutors, she will be sentenced to four months in jail and five years of probation.
Beatty was charged with perjury, misconduct and obstruction of justice. She and Kilpatrick were accused of lying during a whistle-blowers' trial about being romantically involved.
Kilpatrick is serving a four-month jail sentence as part of a plea to two charges.