A cord lock and release system for use in a window blind assembly. The system has a stationary member, a locking member and a movable segment. The locking member is positioned so that at least one lift cord can move across a portion of the locking member when the locking member is in an open position. The lift cords will be restrained by frictional contact with the movable and stationary members when the locking member is in a locked position. The locking member is biased towards a locked position. A release linkage is attached to the movable member so that when a force is applied to the linkage the movable member moves the locking member toward the open position.