Based on a sample of venture capital (VC)-backed IPO firms, we examine whether tolerance for failure spurs corporate innovation. We develop a novel measure of VC investors' failure tolerance by examining their willingness to continue investing in underperforming ventures. We find that IPO firms backed by more failure-tolerant VC investors are significantly more innovative and VC failure tolerance is particularly important for ventures that are subject to high failure risk. We show that these results are not driven by endogenous matching between failure-tolerant VC firms and start-ups with high ex ante innovative potential. We also examine the determinants of the cross-sectional heterogeneity in a VC firm's failure tolerance. We find that both capital constraints and career concerns can negatively distort a VC firm's failure tolerance. Less experienced VC firms are more exposed to these distortions, making them less failure tolerant than are more established VC firms.