Market failures which have a significant share in the collapse of the free market economy reveal the necessity of government intervention. Market failures like moral hazard, asymmetric information and externalities have put an end to free market economy in many countries. In this study will be placed on externalities the reasons for market failures and environmental taxes are used as a means of prevention these externalities. The main objective of the study is the role of environmental taxes in the prevention of environmental pollution. Thesis of this study is to reach the target; alternative methods are to locate analyzing the effectiveness of environmental taxes.