The operation theater has been become the most important part in each hospital because of scarce and costly resources. So, scheduling is so important in this unit. As a result, in this study operation theater scheduling and rescheduling with consideration of priority surgical patients in Isfahan specialized Hospital has been investigated. The purpose of scheduling is to minimization patient waiting time, surgeon idle time among surgeries and penalty of deviation from operating room preferences. For solving this problem, a mathematical model has been represented. The solving time and the number of unsolved problems are increased dependent on the number of patients and the ratio between the number of patients -to- the number of surgeries. For this reason, three heuristic algorithms are represented for solving the problem. The first one is hybrid greedy heuristic algorithm. This algorithm has improved the samples of Khanevadeh Hospital in a short time. However, it has higher average than mathematical model. Therefore, heuristic algorithm based on mathematical programming has been represented. The ratio between relative deviation average -to- mathematical model is 1.32%. Then, heuristic algorithm based on mathematical programming with local search has been represented. This algorithm has obtained equal optimal solution or near optimal in all samples. So that, the ratio between relative deviation average -to- mathematical model is 0.02 percent. After that, heuristic algorithms performance have been investigated by increasing the number of patients and reduce the number of recovery beds. In all cases, heuristic algorithm based on mathematical programming with local search has better performance than the other two algorithms. As a result, this heuristic algorithm is the best algorithm in the solving techniques provided. Finally, operating room rescheduling problem in Isfahan Khanevadeh specialized Hospital was raised and investigated. Due to solving this problem, rescheduling heuristic algorithm was used. By using this algorithm, the initial schedule had the fewest changes to reschedule.
