Abstract: A holder for retaining and storing individual data diskettes, especially 31/2 inch diskettes. The holder defines a receptacle that secures the diskette along three side edges, and in the direction normal to the plane of the diskette. A binder on the side edge of the holder includes holes for inserting the device in a file folder. The device includes a flat resilient pressure element pressing against one side of the diskette, and a holding catch facing the pressure element so as to engage complimentary recesses in the confronting side of the diskette. Side connecting devices are formed on opposite sides of the devices, for interconnecting several such devices.