We surveyed seven Green Mark certified air-conditioned commercial buildings (666 responses) in Singapore about their satisfaction with the indoor environment. We used a 7-point scale to evaluate subjects' satisfaction with 18 Indoor Environmental Quality (IEQ) parameters. We also asked follow up questions on the reason(s) of dissatisfaction. We found that occupants were most satisfied with dress code (85 % satisfaction), electrical light (84 %) and cleanliness (81 %), while they were most dissatisfied with sound privacy (40% dissatisfaction), personal control (29%) and temperature (29%). Nevertheless, about 78 % of the participants expressed satisfaction with their overall workspace environment. Our results indicate achieving a high occupant satisfaction for some IEQ factors is harder than others. We determined that the major contributors to thermal dissatisfaction were insufficient air movement and overcooled workspace. Occupants in open plan office were unhappy with the noise produced by their nearby colleagues. We identified satisfaction with cleanliness was the most significant IEQ factor that contribute to overall workspace environment satisfaction. In addition, applying principle component analysis, we found that new components that integrated by multiple less significant IEQ factors could also initiate substantial impact to overall workspace satisfaction,including Air, Acoustics, Layout and the Thermal environment. IEQ satisfaction targets rating system in Green Mark (Singapore green building standard) could be improved by evaluating the actual occupant satisfaction responses from a large database to achieve reliability and representativeness. These results can be included for further development of an IEQ benchmarks for commercial buildings in Singapore.