Design-Manufacturing Integration (DMI) is a new and growing research field in Operations Management. The primary goal of the Dissertation is to identify and measure the DMI impact on manufacturing operational performance. The research findings point to a paucity of rigorous empirical research on the impact of DMI on manufacturing operational performance under the lens of moderating effects of market uncertainty and market complexity. Data from 725 metal products and machinery manufacturers (ISIC 3.1, code 28-35) in 21 countries from the fifth round of the International Manufacturing Strategy Survey was used for hypotheses tests. Scales were validated with confirmatory factor analysis and analyzed with hierarchical stepwise multiple regressions. DMI positively impact on the three dimensions of manufacturing operational performance (quality, flexibility, and delivery). Manufacturing complexity moderates flexibility and delivery but not quality. Market uncertainty did not appear as a moderator for the relationship between DMI and manufacturing operational performance. Practitioners should pursue DMI implementations, under higher levels of manufacturing complexity. Further research should focus on market uncertainty, and strengthen the construct of uncertainty with technological uncertainty.