Fifty one subjects aged six to fourteen years old were studied in an "auditory oddball" event-related potential (ERP) paradigm. Our results found P3 as the most consistent component of ERPs since childhood, although a great variability in the latency of this component was found at six years old. An additional group of adults (19-23 years old) was included as a reference group. Separate age/P3 latency linear regressions were computed for subjects 6-14 and 6-23 years old. Our data shows in both groups a significant negative correlation between age and P3 latency. The age/P3 latency slope for the subjects under 15 years old was -19.00 msec/year, versus -8.15 msec/year for all the subjects (6-23 y/o). Our results indicate that P3 latency during childhood decreases with age reaching an asyntote after or during the second decade of life. A significant age/P3 latency curvilinear relationship was found from six to twenty three years old.