This paper presents direct evidence on how firms' innovation is affected by access to knowledgeable labor through co-worker network connections. We use a unique dataset that matches patent data to administrative employer-employee records from "Third Italy"- a region with many successful industrial clusters. Establishment clo- sures displacing inventors generate supply shocks of knowledgeable labor to firms that employ the inventors' previous co-workers. We estimate event-study models where the treatment is the displacement of a "connected" inventor (i.e., a previous coworker of a current employee of the focal firm). We show that the displacement of a connected inventor significantly increases the hiring of connected inventors. More- over, the improved access to knowledgeable workers raises firms' innovative activity. We provide evidence supporting the main hypothesized channel of knowledge trans- fer through firm-to-firm labor mobility by estimating IV specifications where we use the displacement of a connected inventor as an instrument to hire a connected inven- tor. Overall, estimates indicate that firms exploit displacements to recruit connected inventors, and the improved capacity to employ knowledgeable labor within the net- work increases innovation.