Dr. Kermit Gosnell is already serving life without parole in the deaths of three babies born alive at his Philadelphia clinic.
Authorities say the 72-year-old Gosnell ran a "pill mill" by day and a rogue "abortion mill" by night.
The investigation into his abortion practices came after federal agents raided the clinic over allegations he was flooding city streets with the widely abused painkillers.
Gosnell has twice come to federal court for a plea hearing, only to balk at the deal.
His lawyer, Jack McMahon, says Gosnell signed the latest plea agreement over the weekend, and is due in court for the plea on July 9.