Objective:: The purpose of the current study is to examine the performance of children with and without ADHD in time reproduction tasks involving variation in time durations and visual modality. Method: Fifteen children with ADHD from a pediatric psychiatric clinic were selected using a ADHD rating scale and Conners parents scale and were compared 15 healthy children  from two  schools in Mashhad. Time reproduction tasks for visual modality were in six time durations (6 second, 12 seconds, 18 seconds, 24 seconds, 36 seconds, and 48 seconds). Results: The  main effects of group and task time duration were confirmed (the accuracy decreased as the temporal duration increased).Furthermore,  interactions between group and task time duration were approved (the discrepancy in performance between the two groups grew as the temporal duration increased). Conclusion:  The children with ADHD have more problems in time perception than healthy children and their problems would be greater with greater time durations.