This study investigated the changes in synchronization of different electroencephalogram (EEG) bands in attention deficit hyperactivity disorder (ADHD) children. EEG data were obtained from 13 children diagnosed with ADHD and 13 normal control children in the resting state. The statistical dependencies between each EEG channel were generated by calculating synchronization likelihood. The differences of synchronization between the ADHD and control groups were statistically evaluated. Overall, the synchronization was significantly higher in the ADHD group in the alpha and beta bands. The present study found that synchronization was significantly altered in the fast EEG bands in patients with ADHD. These findings may enhance our understanding for the relationship between ADHD and cerebral dysfunction.