This study examines the importance of public research and development (R&D) expenditures and innovations (prices) to U S agricultural productivity employing panel vector error correction econometric technique Specifically, time-series and panel unit root tests, panel cointegration procedures, panel causality tests, and vector error correction model are used in the analysis. Empirical application to U S state-level data for 1960-2004 suggests positive and statistically significant influence of both supply-side drivers, in the form of public R&D expenditures, and demand-side drivers, in the form of innovations (prices), on total factor productivity growth.