<p>  This case report describes the use of ultrasound-guided glossopharyngeal nerve block (UGPNB) and intravenous sedation (IVS) to control a gag reflex (GR). A 45-year-old man (178 cm, 102 kg) with a severe GR attended our hospital to receive dental treatments under anesthetic management. The patient did not have any comorbidities other than obesity (body mass index of 32.2 kg/m²) and was not taking any medications. We used IVS for the first treatment but experienced difficulty inserting the dental suction cannula and controlling the GR. Subsequently, we used UGPNB with IVS for the remaining treatments and were able to insert the dental suction cannula and control the GR successfully. For UGPNB, the ultrasonic probe was positioned in the posterior mandibular ramus and set parallel to the sternocleidomastoid muscle. The resulting ultrasound images clearly delineated the sternocleidomastoid muscle and stylohyoid muscle. A 25-gauge, 25-mm needle was inserted under the stylohyoid muscle through the sternocleidomastoid muscle using an out-of-plane technique. No complications related to the UGPNB occurred. Conventional UGPNB targets an area in the vicinity of the styloid process. This area contains the internal carotid artery, internal jugular vein, external jugular vein, vagus nerve, hypoglossal nerve, and facial nerve. Other approaches target the distal parapharyngeal space ; however, these approaches are associated with a risk of puncturing the facial artery and infecting the submandibular salivary gland. Our sternocleidomastoid muscle approach enabled blood vessel punctures and infection of the salivary gland to be avoided. Therefore, this approach to nerve block has advantages for the management of dental treatments that are repeatedly performed in outpatient settings. The collection of additional patient data is needed for the dissemination of this new approach to performing nerve blocks.</p>