Gas and steam engine power plant (PLTGU) is a power plant with a combined operating system. PLTGU produces electricity with hot and steam media to rotate turbines coupled with generators. In Law No. 15 of 1985 a power plant is required for its reliability to produce electricity. However, operational activities in PLTGU are not fully implemented as planned. Various factors can trigger the occurrence of interference. Making efficient and reliable power systems requires good management. Therefore, anticipation of the risk of failure is required. This study aims to determine and manage the possibility of operational failure risk in PLTGU so it is expected to be a reference in anticipating the risks that result in loss of electricity production. The research process refers to the International Organization for Standardization (ISO) 31000 using a risk matrix. The process is performed on PT X by identifying and analyzing risk. Through the risk matrix obtained 3 the highest value of the risk of failure. Three risks with the highest value were analyzed using Failure Mode and Effect Analysis (FMEA) method. It is known that there are risks that affect the operational factors of PLTGU such as low fuel supply, cooling system disrupted and risk of Circulating Water Pump failure. So it can be determined the treatment of the risk of failure in the form of not advanced according to the cause of the risk.