This paper establishes labor scarcity as an important economic channel through which access to finance shapes technological innovation. We exploit antebellum America, a unique setting with (1) staggered passage of free banking laws across states and (2) sharp differences in labor scarcity between slave and free states. We find that greater access to finance spurred technological innovation as measured by patenting activities, especially in free states where labor was relatively scarce. Interestingly, in slave states where slave labor was prevalent, access to finance encouraged technological innovation that substituted for free labor, but discouraged technological innovation that substituted for slave labor.