Terrorist attacks on Electricity infrastructure, a special kind of disaster, are capable of causing large economic losses and disruptions of service. Demand reduction, higher operating costs for the electricity sector, the costs of repair or replacement of towers, and the impact on users are some of the most important effects of such attacks. This article summarizes the impact of terrorism on transmission lines and security of supply in Colombia's power system during the last 11 years. Attacks on the electrical infrastructure, power failures, restoration procedures after a blackout, the development of constrained transmission, the impact of the related costs on business profitability, recovery costs, and the lessons learned from emergency situations are the principal topics discussed.