The health expenditures have increased in recent years, both in Brazil and in most developed countries. To address this issue, public and private players have sought to improve the efficiency and effectiveness of health systems, notably through the planning and control in healthcare. A unit that is of particular interest in hospitals is the operating theater as is often the largest cost unit and also higher hospital revenue, generating great impact on the performance of the same. However, in most Brazilian hospitals, decisions regarding the management of beds and operating room management are taken from tacit knowledge and empirical observation. Thus, the study aims to apply appropriate analysis technique, such as process modeling and Monte Carlo Simulation to provide a better-structured decision-making in relation to the planning and programming of surgeries. A case study was conducted at a public hospital in order to achieve improvements in the planning process of surgery and decrease in suspensions index. As a result were proposed amendments to the hospital s surgery planning process and suggested to standardize the number of surgeries markings with ICU indication for 5 or 6 markings daily to reduce the suspension rate due to lack of vacancy in that unit.