Sudden sensorineural hearing loss (SSHL) is a symptom of cochlear injury. It is characterized by sudden onset, and, within a few hours, it reaches its maximum peak. It may be accompanied by vertigo and tinnitus. Many hypotheses have been advanced to explain its etiology: viral inflammation, vascular diseases, allergic reaction, rupture of intralabyrinthine membranes, and autoimmune diseases. The decrease in hearing may be unilateral or bilateral. To assess the histopathology of the labyrinth in cases of SSHL and to provide a better understanding of the etiopathogenesis, many studies have been carried out. Atrophy of the organ of Corti, loss of cochlear neurons, labyrinthine fibrosis, formation of new bone, and degeneration of the spiral ligament, vascular stria, hairy cells, dendrites, and apical spiral ganglion cells have been reported in temporal bone studies. In this article, new studies on the histopathologic and therapeutic bases of SSHL are reviewed.