Firm growth and profitability come primarily from new product development. Portfolio management has been emphasized in improving new product development (NPD) performance under multiple project environments. However, few researchers have demonstrated the consequence of different combinations of portfolio management practices on NPD performance.In this study, a decision support methodology based on Bayesian network scenarios is used to simulate the effect of portfolio management on NPD performance in uncertain environments. Portfolio management (PM), the extended application of investment portfolio theory to new product development (Cooper, Edgett, & Kleinschmidt, 1999), has been widely recognized as a crucial technique to improve NPD performance, especially for project-based organizations. As a strategic tool, portfolio management is about making important decisions including NPD project selection, resource allocation and balancing NPD projects (Cooper et al., 1999). Therefore, firms need to address the issues about how to conduct PM to realize strategic objectives (Lerch & Spieth, 2013).