The aim of the present study was to investigate the efficacy of the combination of parental training in behavioral management techniques in children with aggressive behavior along with cognitive behavioral treatment applied to children, as compared to the sole treatment of children. The effects of both type of treatments (combined and treatment alone) at posttest were also analyzed from a traditional statistical approach, as well as from the point of view of its clinical significance. Also, the effect of treatment was explored in children’s social functioning and parental stress. According to statistical analyses, both conditions decreased children’s aggression and social problems as perceived by their parents; however, only combined treatment was clinically significant. Parental stress did not change after treatment in either group.