The focus of the study is to observe and analyze control-oriented occupants' behavior toward lighting, shading and natural ventilation systems based on a long-term study in two office buildings. Internal and external parameters; state of occupancy, state of lights, indoor and outdoor illuminance, temperature, relative humidity, state of shades and windows were continuously observed and recorded every five minutes over the period of 9 and 12 months. Subjective impressions and attitudes of observed building occupants were documented with questionnaires. Based on the results from this research, operation of the building systems partly depends on indoor/outdoor conditions. Therefore, it is necessary to have accurate information about user control behavior in office buildings in order to predict building performance and energy consumption. These behavioral patterns can be used to develop empirically supported predictive models for control oriented occupant actions in buildings, building simulation programs, building automation systems, energy management and energy contracting to improve energy effectiveness, occupants' comfort and innovation of user interfaces products.