Purpose The purpose of this paper is to gain knowledge on the impact of customer integration on the new product development of chemical companies in growing markets. The literature affirms the value of customer integration in the new product development, but it is relatively silent on the integration of value-adding partners, who are located further down the value chain. Considerable research has shown that organizations are more successful, when they integrate customers and suppliers into the product development and design process. The research described herein juxtaposes two modes of current theory on customer integration and refines and expands the existing theoretical framework. Hence, the purpose is to build theories from cases to provide an answer to the question of how an organization adopts customer integration by refining the understanding of the different roles of value-adding partners in the innovation process. Design/methodology/approach The paper uses an extended case method, including the resource-based view, literature related to the customer integration and four cases as a basis for establishing theoretical framework. Several in-depth interviews were conducted to gather information on the managerial practice to strengthen the grounding of theory. Findings An explorative study provides a value chain-oriented theory for chemical companies to improve the efficiency of the product development process. Therefore, it differentiates between the integration of direct and indirect customers. Each party can bring in complementary resources, which are not available internally. The findings show that integration of indirect customers contributes to more accurate anticipation of market needs. This allows companies to increase their success rate for new product development (NPD) activities. Research limitations/implications The results of this explorative study cannot be generalized, as theory building from case studies stands on its own analytic unit. Therefore, scholars are encouraged to test the proposed propositions using quantitative data and to apply them in other industrial sectors. Practical implications The paper includes implications for the development of a more efficient research and development, as well as launch, process of radical innovation of chemical companies. Originality/value This is one of the first studies using a value chain-oriented approach for customer integration during new product development.