Despite a longstanding interest in the potential substitution of labor and capital, limited empirical evidence exists regarding the causal relationship between labor supply and the development of labor-saving technologies. This study examines the impact of exogenous changes in regional labor supply on automation innovation by leveraging a German immigrant allocation policy during the 1990s and 2000s. The findings reveal that an increase in the low-skilled workforce reduces automation innovation, as measured by patents. This reduction is most pronounced for large firms within the manufacturing sector and primarily concerns process-related automation innovations. This suggests that the effect is channeled through changes in internal demand for automation innovation. Consistent with a labor scarcity mechanism, the effect is confined to tight labor markets.