Hoarseness is most often caused by a problem with the vocal cords. The vocal cords are part of your voice box (larynx) located in the throat. When the vocal cords become inflamed or infected, they swell. This can cause hoarseness. The most common cause of hoarseness is a cold or sinus infection, which most often goes away on its own within 2 weeks. A rare but serious cause of hoarseness that does not go away in a few weeks is cancer of the voice box. Hoarseness may be caused by: Acid reflux (gastroesophageal reflux)