OBJECTIVE This study sought to better characterize the contributions of deficits in attention allocation and distracter inhibition to the poor performance on attention tasks often seen in children with ADHD. METHODS Electrophysiological (Nd, P3b) and behavioral measures (speed and accuracy) were examined during an auditory selective attention task in children with ADHD, children with typical development (TD), and adults. Thirty children (15 ADHD; 13 females) between the ages of 7 and 13 and 16 adults (8 females) participated. RESULTS Nd waveforms were elicited from adults and children with TD, but not from children with ADHD. Further, those with ADHD exhibited significantly smaller auditory responses at 100 ms (Ta). P3bs were elicited in all three groups by targets but not by unattended deviants. Performance was significantly poorer in children with ADHD than TD and RTs were more variable. CONCLUSIONS Children with ADHD evidenced poorer attention allocation, as measured by Nd and hits, but were not more distracted by unattended deviants, as measured by P3b and false alarms, than children with TD. CONCLUSIONS Findings for Nd, P3b, and Ta considered together suggest that deficits in auditory selective attention in children with ADHD may be attributable to reduced information early in the processing stream.