Cluster policies seek to enhance collaboration among co-located actors as proximity improves interactions and the recombination of existing ideas. However, there is little evidence that place-based policies foster science-industry collaborations. Using data from a national cluster program in France and a novel control group—other industrial clusters—I examine the policy effects on local science-industry co-patent applications. The results show that R&D clusters increase science-industry collaboration. This effect occurs gradually over time, and patents tend to be of higher quality. These results suggest that place-based innovation policies affect the organization of science-industry research within clusters.