A method of treating a patients paranasal sinus, such as the frontal sinus, having an obstructed or narrowed naturally occurring ostium or nasofrontal duct which does not have scar tissue or granulation tissue. A balloon of a balloon catheter is inflated in the obstructed or narrowed naturally occurring ostium or nasofrontal duct to enlarge the ostium or nasofrontal duct. The ostium or nasofrontal duct remains enlarged after the balloon catheter is removed.
