The planning of the maintenance schedule of hydroelectric power plant generating units is a matter of great interest to several agents in the Brazilian energy sector. A correct approach to this problem can prevent the degradation of physical assets and minimize the likelihood of forced shutdown of your equipment. Therefore, the agents operational operations are also influenced by the turbine maintenance schedule. However, the Brazilian system has some particularities, which the economic groups that win the auction for the construction of new hydroelectric plants, meet a series of technical specifications, among them, the Availability Factor (AFA). The AFA is directly influenced by the hours of maintenance performed at the plant and, in case of performance below the stipulated in the concession contracts, it can result in financial losses applied by the regulatory agent. With this motivation in mind, the present work proposes a methodology for Programming the Maintenance Schedule of Generators of a hydroelectric plant, developing a mathematical model to determine the ideal moment to carry out the maintenance, considering operational restrictions and regulatory aspects of hydroelectric plants. The work also offers to obtain a ranking of the turbines using the Analytic Hierarchy Process (AHP) method, based on the maintenance indicators of the studied hydroelectric plant. The purpose of the generated classification is to provide subsidies to assist the planning of maintenance, in order to increase the availability of equipment. The optimization methodology proposed for this problem is done through Mixed Integer Linear Programming (MILP), where the entire variables consist of the state of operation and start data for the maintenance of each generating unit. The representation of the hydrothermal park is challenging, mainly due to the stochasticity of the affluent natural flows. At the end, to validate the proposed modeling, a case study is carried out for a real large plant in the Brazilian system, the Santo Antônio Hydroelectric Plant.