Poor air quality arises by and large from inadequate ventilation and presence of contaminants. In particular to hospital environments, it exercises direct and significant influence over infections occurrence. The purpose of this paper is to research, through computational fluid dynamics, how ceiling (four-way supply) and sidewall (conventional high supply) inlets systems, as well as outlet (exhaust) positioning, effect air motion and distribution in operating rooms. By the assistance of numerical modeling, four alternative scenarios of a operating room were investigated, maintaining flow rates and varying inlet system and outlet position. The results are presented in terms of velocity vectors and temperatures, which were compared to the experimental data available. Subsequently, a qualitative analysis regarding conformity to sanitary requirements was conducted.