The "Star Wars" and "Shattered Glass" actor claimed in a lawsuit filed this week in Manhattan federal court that the basic cable network's series borrows heavily from "Housecall," a show he discussed with NBC in 2005, the New York Post said.
NBC is the parent company of USA Network.
The Post said a USA spokeswoman declined to comment on the lawsuit.
The report didn't say what damages Christensen is seeking.
"Royal Pains," now in its second season, is about a freelance doctor who treats the medical problems of the rich and famous.