This book aims at improving the Architectural Design Efficiency of the work-space environment through the integration of FM process into the architectural design of office buildings. The book monitors the common problems affecting the performance of the work-space environment through a comparative analysis for selected office buildings. However, the integration between Facility Management(FM) and Architectural design is necessary nowadays in order to improve architectural design efficiency, enhance building performance, and decrease the early demolition of new constructed buildings. FM has an excellent effect on increasing the performance of the building, only if it involved from scratch (from the design phase process). The impact of FM is obvious in the results of each building performance. The influences of users about the Functional, Technical, and Behavioural aspects of selected office building, were depicted through a questionnaire. Then the results were analyzed statistically by using mean values and percentages. Accordingly, this interrelation helps enhancing the continuous improvement of building design.