A review was presented of cochlear morphology associated with hearing loss from overexposure to noise. The morphology of the normal cochlea, which is very similar in different mammals, was described. A total of 20,000 to 25,000 hair cells, which transduce mechanical movement into neural impulses, is divided into one row of inner hair cells and three rows of outer hair cells. The hair cell is usually the first to show signs of damage from ototraumatic exposures. However, abnormal morphology in specific regions of the cochlea has often failed to correlate with audiometric or physiologic measures of frequency sensitivity for that region, and attention to subtle aspects of hair cell morphology is required. Some of the hair cell conditions associated with noise exposure have been loss of hair cells, alterations of the hair cell stereocilia, gross deformations of cell bodies, protrusion of the cuticular plate, proliferation of the endoplasmic reticulum, and increase or migration of intracellular constituents. Twenty one light and electron micrographs showing the normal cochlea and pathological conditions were discussed. The author concludes that little can be done medically or surgically to correct damage in the cochlea, so that it is imperative to take steps to avoid exposure to dangerous levels of noise or other ototraumatic agents.