Definition: Tinnitus is defined as a sound perceived more than five minutes at a time in the absence of any external acoustic or electrical stimulus to the ear and not occurring immediately after exposure to loud noise, phantom auditory perception, or head noise. Types: There are two types of tinnitus- Subjective tinnitus– Here tinnitus audible only to the patient. May be due to sensorineural hearing loss due to any cause. Objective tinnitus– Here tinnitus audible not only to patient, but also to the examiner. It usually caused by arteriovenous malformations, glomus tumors, palatal or tympanic myoclonus. Aetiology: I. Vascular somatosounds– Vascular lesions, either arterial or venous, can produce turbulent blood flow, leading to pulsatile somatosounds. They include: a) Vascular tumors- Glomus tympanicum or jugular, Hemangioma. b) Vascular malformations- Arteriovenous malformations, aneurysms, fistulae, carotid artery stenosis, transverse sinus stenosis. c) Increased intracranial pressure- venous hum. d) Transmitted cardiac murmurs. e) Different hyperdynamic vascular states- pregnancy, hyperthyroidism, anaemia. II. Myogenic somatosounds- The most common forms are palatal and less common middle ear muscles, tensor tympani and stapedial myoclonus. III. Patulous eustachian tube- It leads to to-and-fro movements of the tympanic membrane, synchronous with nasal respiration which can be perceived as ‘blowing’ sound or their own voice reverberation. IV. Temporomandibular joint abnormality– It causes audible vibratory sound arising from jaw clenching. V. Spontaneous otoacoustic emissions can be the reason of tinnitus.