In this paper, technical procedure for developing energy performance label for office buildings in Iran is presented. According to inappropriate energy consumption indexes of the office buildings in Iran, present research was conducted for this group of buildings. For this purpose, a building energy simulator software tool was developed, validated, and applied to simulate an exhaustive sample society of office buildings. A widespread field activity was conducted to gather the modeling data from 285 office buildings through all the 4 climatic zones in Iran. Moreover, Reference Buildings as the energy efficient buildings were defined and modeled in the software environment. Energy consumption indexes from modeling of sample society and Reference Buildings were applied to conclude the boundaries for grades A-G of the label. Finally, the label appearance was designed and authorized to be applied for both the existent and new buildings. The upper limit for grade A is determined as: 84, 75, 78, and 82 (kWh/Y/m(2)) and the upper limit of grade G (the failing point) is concluded as: 588, 525, 546, and 574 (kWh/Y/m(2)) for cold, mild, hot and dry, and hot and wet climatic zones, respectively. (c) 2013 Elsevier B.V. All rights reserved.