The traditional procurement and contracting method within the architectural, engineering and construction industry is often criticised for its fragmented approach and its isolation of designers from contractor and Facilities Management(FM). However, adversarial relationships often occur among the project-team members due to disagreements relating to poor communication, processes, specifications, compliance, cost overruns and the extension of times. Therefore, the integration of FM’s specialists into early design development process comes with challenges, such as conflict between the design team and FM’s specialists over the specifications, local statutory compliance, commissioning method statements and the hand-over process. Furthermore, conflicts have critical effects on cost and schedule in complex projects and creates breakdown of relationships among project participants and results in project delays, claims and disputes. The Purpose: The main purpose of this study was to “to explore effective involvement of FM specialists in the early design-development process of complex building projects in South Africa is perceived to be causing conflicts between the multi-disciplinary professional design team members.” Design/methodology: Mixed methods was adopted for this study including extensive related literature review and pilot study. Purposive (8 interviews) and snowballing (102 participants) sampling techniques were used in data collection. Findings: According to descriptive analysis, participants slightly greed that FM specialists should be involved in the early stage of the design development process with mean score ranging from 3.21 (Inception stage) and 3.71 (Concept and Viability stage). Participants agreed that that FM specialists should be involved during design development stage with a mean score of 4.19 and project close out stage with a mean score of 4.29. Furthermore, from 41 causes of conflicts, 10 received mean scores ranging from 2.66 and 2.97 meaning that there is a low possibilities of causing conflicts while 31 variables received mean scores ranging from 3.00 to 3.97 meaning that there is a moderate possibilities of causing conflicts among FM specialists and design team during design development process. Research limitation/Implications: Potential participants are architects, engineers, project managers, property-development managers and facilities managers. Furthermore, the focus of the study is on medium and large complex projects with buildings systems. In addition, this Originality/Value: The high costs of maintenance during operation and non-compliance with the local statutory requirements of the building systems will affect the results and the application thereof. The integration of the design team and FM’s specialists will provide the client with the final product that is functional and safe to occupy and use for its intent. Furthermore, FM’s specialists’ involvement early in the design-development process would reduce operational and maintenance costs during the operational stage of the building; and they would further ensure that the facility complies with the local statutory requirements. / Dissertation (MEng)--University of Pretoria, 2020. / Construction Economics / MSc / Unrestricted