The number of cases involving human death has increased due to scattered virus in the air. This has become a major concern on air quality, especially indoor air quality. The chemical compounds found in the building have limited exchange of outdoor and indoor, which results in building of contaminants such as CO2 emitted by occupants activity in the building. The usage of air conditioner is unable to removes pathogens because its only circulates in air within the area. Medical Centre has a very high potential to centralize the patient with diseases related to health problems such as asthma, respiratory and cardiovascular related-diseases. This study is conducted at medical centre of NDUM, in Kuala Lumpur. The number of patients admitted was compared to the level of CO2, temperature and relative humidity in the Medical Centre. The outdoor air index is collected from DOE Malaysia. Wireless Sensor Network (WSN) is used in this system as it can collect and disseminate the environmental data. Zigbee with 2.4GHz band is used as the wireless standard for the measurement. Sensors were attached to several points at the wall of the waiting room and were controlled by the PC module. Lab View is used to manage the data acquisition due to its ability to program a real-time system. The collected data of temperature, relative humidity and level of C02 determined the indoor air quality in the medical centre. This study brought to the assessment on the medical practice and the air quality that met the standard suggested by ASHRAE.