Abstract: A protective cover for a stringed musical instrument is formed by a single fabric panel that has a peripheral edge passage for a pull cord. The cord is equipped with an adjustable clamp that can be tightened on the cord to hold the cord in a tensioned condition for stretching the fabric panel around the sound box of a musical instrument. The cover material is a stretchable elastic material that conforms to corners and irregular surface contours on the sound, so that the cover achieves a form fit on the instrument.