Economists commonly assume that technological change· is responsible for shifting production functions. Yet few studies have attempted to link productivity change to the adoption of major technologies. This paper examines some of the major technologies that are believed to affect agricultural productivity . Although multicollinearity limits the evaluation of individual technologies, there is conclusive evidence that a few major technologies ere responsible for the bulk of productivity change during this century, Since most of the major technologies were fully exploited by about 1960, productivity increase has slackened since at time. For the future, minor technologies will contribute a modest improvement in productivity but major change will have to await the discovery of new major technlogy.