Abstract Introduction Deep brain stimulation (DBS) is a surgical technique used to manage aggression in patients who do not improve despite the use of appropriate drug treatment. Objective The objective of this study is to assess the impact of DBS on aggressive behavior refractory to the pharmacological and behavioral treatment of patients with Intellectual Disabilities (ID). Methods A follow‐up was conducted on a cohort of 12 patients with severe ID, undergoing DBS in posteromedial hypothalamic nuclei; evaluated with the Overt Aggression Scale (OAS), before the intervention, at 6, 12, and 18 months of medical follow‐up. Results After the surgical procedure, there was a significant reduction in the aggressiveness of patients in the follow‐up medical evaluation at 6 months ( t = 10.14; p < 0.01), 12 months ( t = 14.06; p < 0.01), and 18 months ( t = 15.34; p < 0.01), respect to the initial measurement; with a very large effect size (6 months: d = 2.71; 12 months: d = 3.75; 18 months: d = 4.10). From 12 months onward, emotional control stabilized and is sustained at 18 months ( t = 1.24; p > 0.05). Conclusion DBS in posteromedial hypothalamic nuclei may be an effective treatment for the management of aggression in patients with ID refractory to pharmacological treatment.