Kermit Gosnell, 72, could face the death penalty after his conviction by a jury in a Philadelphia court, the district attorney's office said.
The jury returned guilty verdicts on the three babies, an acquittal in the alleged murder of a fourth, and a guilty verdict in the involuntary manslaughter of a woman on whom he was performing an abortion, DA's spokeswoman Tasha Jamerson said.
The jury, which had earlier Monday declared itself unable to decide on two counts, before going back to try again, had been deliberating for 10 days.
Prosecutors said he performed late-term abortions in a state where the limit is set at 24 weeks and that when babies emerged still alive, he used scissors to sever their spines. However, he denied this, insisting that all babies were already dead as a result of the drug he was using in the abortion.
During one operation in the clinic, described as highly unsanitary, a woman who'd come in for an abortion died from an overdose of anesthesia.