Background and Purpose: Psychological problems of children is associated with several factors such as temperament and personality traits that are biological. The aim of this study was to compare the personality traits with behavioral activation and inhibition systems in students with Conduct Disorder (CD), Attention Deficit Hyperactivity Disorder (ADHD) and normal students.

Method: The research design is causal-comparative. The samples in clinical groups are selected by convenience sampling and the normal group is selected by cluster random sampling method. Eysenck Personality Questionnaire (1975) and behavioral activation and inhibition systems (Carver and White, 1989) are used in the research. Data were analyzed by using multivariate analysis of variance and Scheffe's test.

Results: The results shows that students with ADHD in terms of behavioral inhibition, behavioral activation subscale drive and reward responsiveness are lower than normal group, but in fun seeking, neurosis and psychosis they are at higher level. The group with conduct disorder are at higher level in terms of behavioral activation, reward responsiveness, fun seeking and psychosis, but is lower in behavioral inhibition and subscale drive than the normal group.

Conclusion: The type of personality traits, behavioral activation and inhibition systems are related to behavioral problems, impulsivity, and risk-seeking in students. Therefore, considering to this area of problems can provide effective solutions to professionals and parents.