Abstract: An operating system for a retractable covering for an architectural opening wherein one edge of the covering is fixed and the opposite edge is movable between extended and retracted positions, includes an endless cord loop having a finger slide that is slidably mounted adjacent to the fixed edge of the covering to effect circulation of the cord loop. Also included in the cord loop is an anchor plate secured to the fabric of the covering adjacent to its movable edge, with the anchor plate also moving with circulatory movement of the cord loop to move the movable edge of the covering between extended and retracted positions. The tension in the cord loop is adjustable through the connection of opposite ends of the cord loop to the finger slide and the routing of the cord loop is directed through cord guides of low friction material so that the entire operation of the covering is smooth and reliable.