Temperature-controlled radiofrequency reduction (TCRF) of the tongue base has been developed as an alternative option for the treatment of patients with obstructive sleep apnea syndrome. The technique is propagated as an easy and safe surgical method. The case of a 34-year-old male patient with obstructive sleep apnea syndrome who underwent TCRF is reported. Fourteen days after surgery was performed, heavy bleeding at the base of the tongue occurred. Computed tomography and digital subtraction angiography imaging revealed a pseudoaneurysm of the lingual artery, which was treated endovascularly by detachable and free platinum coils during the same session. The article reports the first case of pseudoaneurysm under TCRF of the tongue base and discusses the diagnostic and therapeutic procedure to handle and avoid life-threatening complications under this method of treatment.