Occupant satisfaction with indoor environmental quality (IEQ) in office buildings has been completely related to self-estimated job performance and, probably, to overall company productivity. Poor indoor environmental circumstances can negatively affect occupants' physical health through poor air quality, extreme temperatures, excess humidity, or insufficient ventilation and psychological health through inadequate lighting, acoustics, and ergonomic design. Sustainable or green building rating systems is attempting to address IEQ and occupant health concerns by providing healthier building environments. Although many qualitative studies claimed that improved IEQ also improves health and productivity and has provided substantial motivation to build green, quantitative studies are needed to prove these relationships. This research shows an outline of the results from a post occupancy evaluation (POE) study on indoor environment, occupant health, and wellbeing in two office buildings in greater Cairo: conventional building and green building certified using the Leadership in Energy and Environmental Design (LEED) Rating System; which is owned and occupied by the same origination. Evaluation of IEQ is based on ‘Building Use Studies' (BUS) occupant questionnaire which applied in both buildings. This research highlighted that occupants productivity in office buildings can be enhanced through good building design, and provision of a high quality, healthy, and functional interior environment, that takes consideration of basic occupant needs