Value Analysis (VA) is a collaborative method that could be used to make a decision in the early phase of complex projects. In this framework, Stakeholders are involved into the process of decision-making and project success is facilitated. Systeme Architechting (SA) is a set of processes used for the conceptual phase of the design of complex systems while System Engineering (SE) is the set of processes used for the design phase of the system. The difference resides in the information on which the decision-making is based: it is very abstract in the architecting phase while it is materialized in the engineering phase. In complex projects, Stakeholders are multiple and carry specific technical, social and environmental expectations that define their perceived Value of the project. The aim of this paper is to demonstrate that VA and SA are two complementary approaches to collect and analyse Stakeholder needs in a complex project. The article presents an analysis of the literature review on VA and SA / SE, which shows the complementarity of these approaches to involve Stakeholders in the upstream phases of the design of complex systems. Based on this analysis, an illustration case is proposed to show how to integrate VA into SA to understand the needs of Stakeholders. The article concludes that the two methods VA and SA can be combined to analyze and would allow following several dimensions of Value (economic, social and environmental) within a complex project.