This thesis consists of three self-contained chapters that empirically evaluate the influence of capital costs and occupational regulation on labor demand. In the first chapter, I study the effects of investment tax credits on firms’ input choices in Germany. I find evidence that such a policy has a strong positive direct effect on firm investment and employment, and that positive spillovers between firms lead to sizable further adjustments. In the second chapter, I estimate the firm-level capital-labor elasticity of substitution. I set up a model of firm production with size-dependent capital costs and estimate the model for a German tax policy targeted towards manufacturing firms. The estimated elasticity implies important complementariti...