The operational reliability studies of equipments from the hydroelectric power plant (HPP) are indispensable to obtain data to determine reliability indicators with adequate credibility.To evaluate the operational reliability indicators of the hydro-generator groups from HPP Tileagd, we detailed the analysis to the level of the next subsystems of these: the globe valve (GV), hydraulic turbine (HT), interacting automatic control system (governor + pressure oil group) (ACS), hydro-generator (HG), group transformer (GT)Using statistic data obtained from exploitation of hydro-power plant Tileagd, we composed a compendium with commentary referring to reliability indicators values, the distribution functions of randomized variables.