The Russian spies pleaded guilty to acting as unregistered foreign agents and were sent home after serving 11 days.
"It sends a message to that agency that they will likely not be in a position to do this again for a long while, and it sends a message to every other intelligence agency in every other country that if you come to America to spy on Americans in America, you will be exposed and arrested," said U.S. attorney Preet Bharara.
The spies were exchanged for four Russian prisoners, including a nuclear scientist who insists he's innocent.
The exchange was a clear demonstration of President Barack Obama's "reset" ties between Moscow and Washington, enabling the U.S. to retrieve four Russians, some of who were suffering through long prison terms.
Moscow avoided having 10 spy trials in the United States that would have spilled embarrassing details of how its agents, posing as ordinary citizens, apparently uncovered little of value but managed to be watched by the FBI for years.
After not commenting for days, the U.S. Justice Department in Washington finally announced a successful completion to the spy swap after the two planes involved touched down in Moscow and London.
The Associated Press contributed to this story.
