A pannier bag (10, 10') for bicycles, and the like, comprises a frame (22) shaped to be streamlined in a forward direction of travel of an associated bicycle. A cover (12) arranged on the frame (22) retains same in the desired streamline shape. A three-point mounting arrangement (16) is associated with the frame (22) and cover (12) for mounting them on an associated bicycle in a rigid manner, while a top front to bottom rear zipper (72) provided with a pair of slides (74, 76) permits access to any part of the interior of the bag. A strip (14) of reflective fabric preferably is provided on the outer surface of the cover (12) of the bag so as to run from the front to the rear thereof in order to increase the visibility of the bag, and hence, an associated bicycle, during darkness.