A covering for an architectural opening has a dual cord operating system. The covering may include a head rail, blind panels depending from the head rail, and an operating system. The operating system may include a housing connected to the head rail, a first drive assembly rotatably mounted within the housing and operable to move the blind panels between an extended configuration and a retracted configuration, and a second drive assembly rotatably mounted within the housing and operable to move the blind panels between a closed configuration and an open configuration.