We study how agents respond to performance incentives according to key personality traits (conscientiousness and neuroticism) through a field experiment offering financial incentives for improving maternal and neonatal health outcomes to rural Indian doctors. More conscientious providers performed better--but improved less--under performance incentives. The effect of the performance incentives was also smaller for providers with higher levels of neuroticism. Our results contribute to a growing body of empirical research on heterogeneous responses to incentives and have implications for worker selection.