Abstract: A device for use in replacing a bowstring of a compound bow and for storing a compound bow in a partially de-tensioned condition without the need to retune the compound bow upon replacement of the bowstring. A connector including a socket for holding a bowstring fastener which is fixed on the end of one of the cables, and a retainer for maintaining the connector in engagement with the cable, are located at each end of elongate linking means including a lever-operated tensioner. The device is installed on the cables of a compound bow while the bowstring is installed, and the lever-operated tensioner is used to slacken the bowstring, allowing its replacement or removal. With the bowstring removed from the fastener the tensioning device may be extended to reduce tension on the bow to a value below that existent when the bowstring is installed, without completely loosening the cables. A turnbuckle is provided to enable the device to be adjusted for use with compound bows having bowstrings of various lengths.