As the process of adaptation to the requirements of a global economic environment based on knowledge and innovation, industrial clusters consisting mainly of SMEs continue to make the buzz within the academic world as well as policy makers. However, the empirical results of their effects on innovation are far from unanimous. In this context, we present a conceptual model on the basis of the literature explaining the indirect effect of clusters on innovation through the double putative mediation of inter-firms and industry-science cooperation. This model also focuses on two potential moderating effects. That of inter-organizational trust which conditions the dynamics of cooperation and that of the absorptive capacity to clarify the boundaries underlying to the transformation of cooperation opportunities (Inter-firm and industry-science) into innovation performance. This paper concludes with potential practical implications and suggestions for future research. Key Words: Cluster, Cooperation, Trust, Absorptive Capacity, Moderation, Mediation, Innovation Performance.