The authors studied the effect of noise (110 dB), delivered by an eletric bell, upon parenchima cells of pineal gland of albino female rats. Several experimental groups were previously formed and stimulated during, 1, 2, 4 and 7 days. In addition another group was formed and stimulated during 7 days plus 10 additional stimulations of about 3 minutes each after the routine stimulations in the seventh day. The authors observed that a single stimulation of about 3 minutes was sufficient to determine alterations in the parenchima cells of the pineal of experimental animals; the changes were characterized by picnolisis in some groups, whereas in others groups picnolisis and interstitials vacuolizations were evidently increased directly with stimulation. The results suggest that the sound stimulation has a destructible effect upon the parenchima cells of the pineal gland of the female albino rats.