The charges say, he viewed more than 200 intelligence reports related to Cuba in his last year of employment.
According to court documents, the two were recruited in 1979 by a Cuban official who directed Walter Myers to pursue a job at either the State Department or the CIA.
The couple allegedly received coded messages from Cuba via shortwave radio, and Gwendolyn Myers, who worked as a analyst at a local bank, would pass on information by changing shopping carts in shops, the department said.
The couple also allegedly travelled all over South America and the Caribbean to meet with Cuban agents
Both were charged with conspiracy to act as illegal agents of the Cuban government and with communicating classified information to the Cuban government, the justice department said.
They were also charged with wire fraud and acting as an illegal agent.