Dr. William Conway is due in federal court in Central Islip.
Conway was charged with conspiracy to distribute oxycodone, allegedly knowingly writing prescriptions to people known to be addicted.
In addition, Conway was charged with causing the overdose deaths of two patients in 2011, 34-year-old Giovanni Manzella, of Long Beach, and 29-year-old Christopher Basmas, of Hicksville.
His longtime assistant pleaded guilty earlier this year to conspiracy to distribute the drug and agreed to testify against Conway.
The charges were part of a crackdown by federal officials on the illegal distribution of painkillers by medical personnel.