The inappropriate indoor environmental quality of a building causes different problems such as headache and breathing difficulties which are called the syndrome of building sickness. These diseases reduce the efficiency of people and deteriorate the quality of their life. Studies carried out in hundreds of big office buildings across the world show that the indoor environment qualities of these buildings are about the average and a lot of employees are dissatisfied with their work place. Besides, the studies show that many of employees suffer from diseases associated with buildings. These diseases greatly affect the efficiency and working hours of employees and have grave economic consequences for the countries. If a space, including an office space, enjoys a qualitative interior, the employees`health and as a result their efficiency will improve. Therefore, attending to the indoor environment quality is a must in designing modern office buildings. The present field study was conducted on 10 office building in Kermanshah in winter 1390—a city which is located in a cold climate—and investigated the effect of environmental factors on the office indoor environment quality. The analysis of data by Statistical Package for Social Science Software1 revealed that the variables of suitable view and landscape, and ventilation have had the greatest effect and the sun light variable has had the smallest effect on the indoor environment quality.
