PURPOSE: To conduct a research to verify if long latency auditory evokes potential in full-term and premature infants during the first month of their life. MATERIAL AND METHODS: This research was approved by the ethics committee at Universidade Federal de Santa Maria, Santa Maria, RS, Brazil. After briefing the parents of the infants regarding the methodology, signed informed consent (IC) was obtained. This study comprised 25 newborns (15 full-term [control group] and 10 preterm [study group] infants)in the Newborn Hearing Screening (NHS) during the first month of their life. These infants were considered premature when the gestational age was <37 weeks. The IHS equipment, Smart EP system, was used for the auditory-evoked long latency potentials research. A binaural method was used for the auditory-evoked long latency potential research with insertion phones, stimulation /ba/ with rarefaction click polarity, trapezoidal envelope, 10000usec rise/fall, 50000 usec duration, and 80-dBNA intensity. The infants slept in a normal way.RESULTS: The average gestational age of the full-term born infants was 38 weeks, where as that of the premature infants was 33 weeks. It was possible to observe only P1 and N1 potentials in both groups, but no verified statistical significant difference was observed between the latencies of the components. CONCLUSION: It was possible to observe the exogenous components P1 and N1 of the cortical potentials in full-term and in premature infants. However, no difference was observed between the groups.