The elasticity of substitution between capital and labor features prominently in several areas of economic research. However, a consensus estimate remains elusive. We develop an estimation strategy that filters panel data in an original way and avoids several pitfalls - difficult-to-specify dynamics, transitory time-series variation, and positively sloped supply schedules - inherent in investment equations that can bias the estimated elasticity. Results are based on an extensive panel containing 1,860 manufacturing and non-manufacturing firms. Our model generates a precisely estimated elasticity of approximately 0.40. The method developed here may prove useful in estimating other structural parameters from panel datasets.