The purpose of this study was to explore factors related to the medication compliance by severity levels of children on Attention Deficit Hyperactive Disorder (ADHD) medication. Methods: The method employed in this study was a descriptive correlational and cross-sectional survey design using face-to-face interviews. The survey was conducted from September, to October, 25, 2010 through a self-report questionnaire following consent of 143 mothers. Interview instruments, which were used in the study were CARS, PAI, ADHD knowledge instrument, BDI, a maternal behavior instrument, TAQ, and TAB instrument. Descriptive statistics, t-test, analysis of variance, and Pearson`` correlation were used for data analysis. Results: Mothers who perceived their children as not hyperactive were significantly higher in accepting medication and positive maternal behaviors than mothers who perceived their children as hyperactive. The mother perceived their children as not hyperactive showed positive correlation to adherence with ADHD medication and ADHD knowledge but a negative correlation with depression and children``s ADHD symptoms. There was, however, no correlation between medication adherence and any other variables in the mothers of children with hyperactivity. Conclusion: The results of this study indicate that different approaches are needed according to the severity of ADHD in children on medication and children``s medication adherence.