The operating theater (OT) is one of the most expensive hospital resources, and its management is a very complex task, which involves combinatorial aspects in an uncertain environment (surgical durations, emergency cases, availability of recovery beds). This project is concerned with the tactical  (middle-term) planning of the OT, which aims at maximizing the utilization of resources in the OT, balancing the workload over the different operating sessions, and ensuring an equitable access and treatment duration to all patients.