A construction megaproject is defined in literature as a construction project, or aggregate of such projects, characterized by magnified cost, extreme complexity, increased risk, lofty ideals, and high visibility, in a combination that represents a significant challenge to the stakeholders, a significant impact to the community, and pushes the limits of construction experience. Risk assessment in megaproject is the most difficult component in the risk management process. Although it has high relevance to the success of megaprojects, risk management remains one of the least developed research issues. Megaprojects are executed in a dynamic environment and identified risks are to be prioritised based on their impact on project objectives of time cost and quality before they can be modelled. The present paper focuses on prioritising the technical risks associated with the construction of phase 1of Bangalore Metro Rail Project to assess its impact on the project objectives that helps in the decision support system of the project. © 2017 IAEME Publication.