Are foreign-born scientists different from native-born scientists with respect to research activity and performance? This question has important policy implications not only for immigration policy but also for science policy because a substantial part of scientific research in the United States is conducted by foreign-born scientists. This study examines the differences between foreign-born and native-born scientists in research collaboration, grants, and publication productivity. The data for this study are 443 curricula vitae (CVs) and survey of scientists and engineers that Research Value Mapping Program (RVM) at Georgia Tech conducted from 2000 to 2001. By using the multiple indicators, the findings show that foreign-born scientists do not differ significantly in research collaboration and grants from their native-born counterparts. But in terms of publication productivity, foreign-born scientists are consistently more productive than their native-born counterparts. This study also examines the impact of being foreign-born on research collaboration, grants, and productivity, and which factors account for the differences between foreign-born and native-born scientists in collaboration, grants, and productivity. When other relevant variables are controlled for, being foreign-born still has a strong positive effect on publication productivity. Collaboration and grants have a significant positive effect only on the productivity of native-born scientists, whereas strong research preference of foreign-born scientists contributes to their relatively higher productivity. Differences are also found among foreign-born scientists, largely depending on their national origin categorized by the similarity of language and culture. The theoretical and policy implications are also discussed.