The paper discusses empirical evidence on the relationship between environmental protection and economic performance. Traditionally, economists and managers perceived environmental regulations and pollution abatement as a cost burden on firms and a factor detrimental to their competitiveness and that of the entire economy, Kudłak says. A new approach to this issue appeared at the beginning of the 1990s when Michael Porter suggested that properly designed environmental standards could stimulate innovation, which would decrease a firm’s environmental impact while strengthening its competitiveness through improved productivity. Since Porter published his theory, there have been a growing number of theoretical and empirical papers examining his ideas. Kudłak says his research findings do not justify the view of some politicians, economists and managers that environmental protection poses a threat to the competitiveness of enterprises and economies. On the other hand, there is no hard evidence supporting Porter’s hypothesis, Kudłak concedes. Presumably, environmental protection measures can be a competitiveness-boosting factor, the author concludes, but only under specific conditions.