The purpose of this study is to address the Critical Success Factor (CSF) for implementing Quality Management System (QMS) in Facilities Management (FM) organization.  The objectives of this research are to identify the Success Factor (SF) for the QMS implementation first and then to determine CSF for the QMS implementation in FM organisation.  Initial investigation including literature search and experts’ opinion within facilities management team identified and confirmed twelve SF of QMS implementation which are top management commitment, leadership, commitment from staff, teamworking, staff training, continuous improvement, performance management, communication, IT skills, financial, organizational culture and quality planning.  Having confirmed the constructs, experts’ opinions were sought to develop the relationship among the QMS’s CSF.  Structural Self-Interaction Matrix (SSIM) is used to collect the opinions and using  the Interpretive Structural Modelling (ISM) methodology, the opinion are converted into binary reachability matrix.  Two things are developed using the reachability matrix which are driving power and dependence diagram and the ISM based structural model where both show the CSF for the QMS implementation in FM organisation.