Clinical results in 40 preterm newborns stimulated with maternal voice have been studied in a Neonatal Unit. We compared these results with a control group. After a period of ten days we observed a significant increase (p less than 0.001) in: weight gain (34 g. vs 26 g. per day), an advancement of the hospital discharge time of 3.8 days, spontaneous motor activity, hand sucking and increased interest in the human face. Auditory Brain Stem Response at 35 and 39 weeks, with a total of 21 registered in the experimental group vs 25 registered in the control group, showed that V wave latency decreased significantly (p less than 0.05) in the stimulated group--0.88 m.sc. vs, -0.61 m.sc.--in the control group. These results confirm an enhancement of the auditory way conduction speed from 0.06 m.sc. to 0.53 m.sc. (p less than 0.05).