Foreign-born scientists and researchers have long been a fixture in the U.S. R&D system. This paper examines a key indicator of scientific performance - individual research productivity. In a large sample of public sector researchers in nanoscience and technology, it was found that foreign-born scientists are consistently more productive than their native-born counterparts across different organizational settings and within a federal laboratory environment. The results furthermore show that male foreign-born researchers are more productive than their female peers in an unusually multidisciplinary research environment, except in the federal laboratory system. Both policy and management implications of these findings will be discussed. An open-versus closed-door immigration policy debate has historically resulted in policies that favor an open-door immigration policy for foreign-born researchers, but lately, and particularly since September 2001, the policy pendulum has started to swing in the other direction. I argue that a reasonable and sound immigration and science policy would balance the benefits of having a strong contingent of foreign-born researchers with the interests of current and future native-born researchers. Research-intensive organizations would serve their interests well by initiating or sustaining diversity and equal opportunity employment practices, which are likely to have a positive impact on research productivity.