The following paper describes a new, easier to use approach to the calculation of relative risk levels of alternative pesticides. An insect, a plant disease, and a weed were selected for describing the application procedure of a new ranking method that is based on the intrinsic properties of pesticides rather than on the processes that occur both on land and in water after they are applied to soil. The approach is based on the Toxicity-Human health-Persistency (THP) Hazard Rating System, and a consumption factor is added to the method in order to calculate the environmental risk of pesticides. The available substitute pesticides are ranked in terms of their relative risk levels from lowest to highest in order of magnitude difference. Such a ranking method may be used as a practical quantitative tool to generate significant findings aiding in the selection of the most environmentally friendly substitute against a certain pest, especially in developing countries that still face the misuse and/or unconscious use of pesticides. (c) 2005 Elsevier Ltd. All rights reserved.