This study adjusts 1960-1996 agricultural productivity gains in a panel of Great Plains states to account for the discharge of pesticide and nitrogen effluents into the environment. The agricultural-environmental technology is approximated with translog distance functions that allow us to contrast traditional versus environmentally adjusted productivity gains. Findings indicate technical change has been increasingly biased toward environmentally friendly production. While the environmental adjustment reduced overall productivity gains during the sample period, in recent years adjusted productivity outpaced the traditional measure, reflecting the pro-environment bias in technical change.