Using derivative usage data on over 1746 firms headquartered in the U.S. during the 1991 through 2000 time period, we find that firms with greater agency and monitoring problems (i.e., firms that are less transparent, face greater agency costs, have weaker corporate governance, larger information asymmetry problems, and overall poorer monitoring) exhibit a negative association between Tobin's Q and derivative usage. The negative valuation effect is also economically significant with an impact of -8.4% on Tobin's Q from a one standard deviation change in the firm monitoring index. The results are robust to alternative specifications, time varying estimates, econometric procedures that correct for potential clustering of errors, endogeneity problems, and sample selection biases among other robustness checks discussed in the paper. We conclude that derivative usage has a negative impact on firm value in firms with greater agency and monitoring problems.