In this paper, we present a mathematical model based on the queuing theory that simulates the examination process in a patent office, including its relation with the applicants. Through this statistical model, this study aims at evaluating the examination effort distribution among all examination stages, in order to establish the optimal examination condition, which means that a patent application would be granted, denied or withdrawn in the shortest period of time and the backlog of patent offices would be reduced, meeting the society demand in a more efficient way. This study also aims at evaluating the performance of a specific patent examiner based on the optimal condition.