Deflectable guide catheters and methods, including methods for using defectable guide catheters to perform transnasal procedures within the ear, nose, throat, paranasal sinuses or cranium. Some deflectable guide catheters of the present invention comprise a substantially rigid tube, a helical spring attached to and extending from the distal end of the substantially rigid tube, a tubular plastic inner jacket, an outer plastic jacket substantially covering at least the helical spring member. The spring member is deflectable to cause the distal portion of the guide catheter to deflect to a curved configuration. In embodiments for transnasal use the deflectable guide catheter may have a length of less than 25 cm.