Healthcare facilities provide different types of services to anyone whose health is endangered in a certain way. In order for the treatment to be as successful as possible for the patients and the work of the staff to be more efficient, it is necessary to create a comfortable environment whose essential factors are temperature, humidity and air quality. These factors are controlled by a HVAC system that consists of subsystems for heating, cooling, ventilation and domestic hot water preparation. Unlike other buildings, healthcare facilities have a special criteria for air treatment, especially if they include clean rooms such as operating theaters. This master thesis deals with development of a project solution for a polyclinic located in Osijek. The polyclinic has three floors and each represents a separate HVAC subsystem. In order to select the most adequate equipment, the first step in the design is calculation of heat losses and gains and calculation of the required amount of air for supply and exhaust. A separate calculation was performed for rooms of the operating block that have to meet the highest standards when it comes to purity of the air and regulation of temperature and humidity. For the needs of heating and cooling of almost all rooms except the rooms in operating block and sanitary facilities, a variable flow system (VRF system) was selected. The installation of bathroom radiators is planned for heating the toilets. The operating block is heated and cooled by a special thermal ventilation system that has ability to process air and heating and cooling. Ventilation systems are divided into pressure and exhaust subsystems and separate elements, such as ceiling diffusers, grilles, air valves are chosen. Also, installation of six air handling units for air conditioning for each floor separately as well as for rooms that require special air treatment such as the operating room and X-ray rooms is planned. In order for the entire system to function properly and serve the well-being of patients and staff, automatic regulation system which unites all systems is chosen and represents a particularly important part of this project solution.