This paper reviews the literature on the integration of marketing and R&D functions, emphasizing the need for communication and cooperation in leaner, flatter organizations. It discusses the barriers to integration, such as personality differences, cultural thought-worlds, language barriers, organizational responsibilities, and physical barriers. The paper also examines research models that study integration and proposes a causal map to organize research on integration at the new-product project level. It reviews methods managers use to achieve functional integration, including relocation, personnel movement, informal social systems, organizational structure, incentives, and formal integrative management processes. Each method is evaluated for its effectiveness and the conditions under which it works best. The paper concludes by suggesting researchable hypotheses to link mechanisms to outcomes, highlighting the importance of integrating marketing and R&D for long-term success in the marketplace.This paper reviews the literature on the integration of marketing and R&D functions, emphasizing the need for communication and cooperation in leaner, flatter organizations. It discusses the barriers to integration, such as personality differences, cultural thought-worlds, language barriers, organizational responsibilities, and physical barriers. The paper also examines research models that study integration and proposes a causal map to organize research on integration at the new-product project level. It reviews methods managers use to achieve functional integration, including relocation, personnel movement, informal social systems, organizational structure, incentives, and formal integrative management processes. Each method is evaluated for its effectiveness and the conditions under which it works best. The paper concludes by suggesting researchable hypotheses to link mechanisms to outcomes, highlighting the importance of integrating marketing and R&D for long-term success in the marketplace.