In 1997 the Danish Minister for Environment and Energy set up a committee to evaluate the possibilities of reducing the use of pesticides in Danish agriculture. As an important part of the evaluation the farm economic and macro economic consequences of a reduced use of pesticides in Danish agriculture was calculated. This article describes the farm economic consequences, as well as the agronomic background and the farm economic model developed to calculate these consequences. The analysis was built up around a set of farm types representative for Danish crop rotation regimes and a set of scenarios intended to show the consequences of different degrees of reduction of pesticide consumption in agriculture. For each scenario the crop yield losses, alternative cultivation techniques, and a number of overall restrictions on the crop rotation were estimated and incorporated in the farm economic model. By using the model the new optimal allocation of crops and pesticides was decided for the different farm types and scenarios. It was found that a total ban on the use of pesticides would have considerably economic effects on crop production and require severe adjustment of the crop rotation and cultivation systems. However, the present use of pesticides can be significantly reduced without any drastic economic losses.