OBJECTIVE: To report a case of carotid canal dehiscence with the basal turn of the cochlea, a rare condition that can mimic other diseases and can be fatal if ignored during otologic procedures. There are currently only four cases reported in the literature. CASE REPORT: patient B.C.S., female, 48 years old, complaining of right pulsatile tinnitus for 7 years, type constant, which worsened with the increase in heart rate. No history of dizziness, trauma or ear surgery. Without co morbidities, and had a history: perinioplasty for 13 years ago, total hysterectomy for 8 years ago and varicectomy for 4 years. The Otolaryngological examination showed normal and there were no significant changes in tone and speech audiometry. Tomography of the temporal bones showed dehiscence of the cochlear basal turn with the right carotid canal. CONCLUSION: This condition must be known to all otolaryngologists, because the anatomical proximity between the carotid artery and the cochlea can lead to auditory and vestibular symptoms. Moreover, the "range carotid-cochlea", may vary greatly: from 0.2 mm to 5 mm or be dehiscent, and therefore required a detailed preoperative investigation with imaging with high resolution and meticulous surgical planning, specific to each case before otologic procedures, especially for cochlear implants. Thereby avoiding pathologies that occur and pass unnoticed serious or irreversible iatrogenic.