Psychotropic medications are one of the most widely prescribed medications in the United States. In recent times, the use of psychotropic medications among children especially those with developmental disabilities have increased significantly. Given this background, the purpose of this study is to present three clinical cases of treating aggressive rage behavior in children with developmental disabilities using beta blockers. As autonomic adrenergic activity regulates very efficiently the aggressive rage behavior like fight or flight in healthy adults, this study proposes that unregulated over-activity of the immature adrenergic system may be involved in rage behavior of children with developmental disabilities. In three such patients of ages between 3 to 12 years showing intense, frequent, impulsive, intrusive, aggressive rage behavior along with profuse sweating, pupil dilation and high pulse rate are initially treated with 60mg/day of propranolol and gradually titrating the dose to 160mg/day to control adrenergic symptoms. Within few weeks of this treatment, frequency and intensity of rage also decreased and gradually propranolol was tapered and discontinued after a year. These results indicate that in some children with developmental disabilities rage behavior may be due to unregulated over-activity of immature adrenergic system that can be treated with beta-blockers like propranolol. These studies show the significance of differentiating psychotic rage from adrenergic rage behavior in order to promote judicious use of psychotropic medications among children with developmental disabilities.