WiFi monitoring technology is increasing rapidly nowadays and enables detection of signals that WiFi-enabled devices send out while they search for an Access Point. For this project, passive WiFi monitoring was used to detect users of buildings at TUDelft campus and gain insight into the occupation and use of them, in request of the TUDelft FMVG. The area of interest is the area between the Central Library and the Aula Conference Center. 20 sensors from BlueMark Innovations were located at the Library, the Aula and 5 Faculties for 1 week. Simultaneously, ground truth data was collected for 2 days at the Library and the Aula, using an online questionnaire and a counting application. Due to sheer size, raw sensor data was difficult to process. Hence, it was classified into groups containing all the devices detected by the sensors, resulting to groups for 15 and 60 minutes data per building. However, not all the devices were detected due to their characteristics and also to the limited number of sensors, mainly at the faculties. Furthermore, raw data was filtered from static devices, devices detected during the closing hours of the buildings and devices detected from the outside of the buildings (outliers). Data analysis was the next step included: identification of the occupation of Library and Aula, user groups regarding building use and mapping relations between the buildings. For the visualization part, an online dashboard was developed as a tool to help the client at the decision making process. The dashboard contains information about the sensor network, data analysis and pattern recognition derived from this analysis.