Introduction: Attention deficit/hyperactivity disorder is associated with impulsivity and behavioral inhibition deficits, Risk taking is the important aspect of impulsive behavior.Aim: The purpose of this study was to Comparison of risk-taking regarding behavioral inhibition deficits in attention deficit hyperactivity disorder (ADHD) with and without conduct disorder (CD) and compared with control children.Method: 37 male children with ADHD (23 ADHD only and 14 ADHD with conduct disorder (ADHD+CD)) were selected by purposive sampling method and performed Balloon Analog Risk Task (BART) and Go-Nogo task to measure risk taking and behavioral inhibition, and compared with18 normal children. The data was analyzed by ANOVA, MANOVA and MANCOVA.Results: Data analysis demonstrated that ADHD+CD group has the highest risk taking followed by ADHD and control group without considering of behavioral inhibition; although comparing to control group, ADHD+CD group has meaningless difference by arranging behavioral inhibition deficits, even though ADHD group has the same risk taking scores in compared with control group both considering behavioral inhibition deficits.Conclusion: This finding suggested that ADHD children have impulsivity because of behavioral inhibition deficits, while it would not be able to predict destructive behavior and risky activities in ADHD+CD in compared with ADHD by itself, also it could be a high risk taking pattern.