This study aimed to evaluate the baseline sleep habits of children with ADHD and the effects of treatment with methylphenidate (MPH) and atomoxetine (ATX) on sleep parameters. Treatment naive children with clinically normal intelligence diagnosed with ADHD were enrolled in the study. Children were treated naturalistically with MPH and ATX. Treatments were started at 0.5 mg/ kg/ day and titrated weekly to a maximum of 1.2 mg/ kg/ day. The daily equivalent dose was calculated according to clinician toolkits of Utah Academy of Child and Adolescent Psychiatry. DSM-IV Based Screening and Assessment Scale for Disruptive Behavior Disorders- Parent form (DBSASDBD) and Clinical Global Impression Scale were used to assess ADHD symptoms and Children's Sleep Habits Questionnaire (CSHQ)- Short Form was used to assess the sleep habits and problems before and after the treatment. Both MPH and ATX reduced symptom severity of ADHD in all domains and also reduced total CSHQ scores with similar effect sizes. (0.7 for MPH vs. 0.8 for ATX). The rate of clinically significant sleep problems at baseline was 93.5 %. At the end-point, 83.9 % of the sample still displayed clinically significant sleep problems while none of the children were judged to have moderate-severe sleep problems. Our results suggest that both ATX and MPH may selectively improve different sleep domains in children with ADHD. Studies using standardized dosing schemes for longer durations and evaluating sleep with objective measurements may clarify the differential effects of treatments on sleep among children with ADHD.