Radon is the largest source of natural radiation all people exposed to. It can form in houses due to building materials or enters through cracks in walls, basement floors and with water used in bathroom showers and faucets. The buildings keep radon inside, where it accumulates and may become a health hazard if the building is not properly ventilated. Radon can be inhaled into the lung, and especially short-lived products of its disintegration can cause long-term internal exposure. In this study, indoor radon survey was carried out at several campuses of uskudar and Okan Universities by using AlphaGUARD active radon detector.